This Green Bean Casserole from Scratch recipe will take your Thanksgiving side dish game up a level. It is surprisingly easy to parboil fresh green beans and whip up your own cream of mushroom soup for a flavorful and healthy casserole. You can also easily make it gluten-free and dairy-free if needed so everyone can enjoy it during the holidays.
Normally green bean casserole is passed up at Thanksgiving for the more flavorful and carb-heavy sides. (Like Cajun Cornbread Dressing, Sausage Stuffing, or a Sweet Potato Casserole, for example.)
Most people associate green bean casserole with mushy canned beans, canned soup, and packaged sodium-rich fried onions that could give you a heart attack after eating just one.
But if you’ve never made this Thanksgiving dish completely from scratch, then your tastebuds (and waistline!) are in for a delightful treat.
So to break it down, the recipe you’ll find below is so-freaking-amazing for a few reasons:
- It’s made with fresh green beans, not canned or frozen.
- A homemade cream of mushroom soup recipe.
- The French fried onions are baked instead of fried.
- It is super easy to make ahead of time for that busy Thanksgiving Day!
So read on to learn how to make one of your new FAVORITE Thanksgiving recipes.
Ingredients
To make this Green Bean Casserole from Scratch recipe you need:
- Green beans. Wash and trim green beans into 2-inch pieces. You might see them called string beans, but they are the same. You will briefly boil green beans before making the casserole, as well.
- Onion. A sweet onion is perfect to make your own French fried onions. But you can use a white or yellow one, just steer clear of red onions because of their stronger flavor. Check out how to cut an onion.
- Flour. Either all-purpose or a gluten-free 1-to-1 blend will work.
- Breadcrumbs. Plain, unseasoned is best. Don’t use panko, though.
- Egg. A whisked egg is essential to make your own fried onions for the topping. You can use a flax egg if needed.
- Milk. Regular or plant-based can be used. A full-fat option will create a creamier taste, though.
- Butter. Opt for unsalted butter. You can use a dairy-free alternative if you prefer.
- Mushrooms. Either button or baby bella are easy to find at the store, but any variety will work.
- Garlic. Minced garlic creates a rich, depth of flavor in the homemade cream of mushroom soup.
- Seasoning. You can use what you have on hand, like thyme. But salt and pepper are essential.
How to Make Green Bean Casserole from Scratch
The basic steps for making Green Bean Casserole from Scratch are simple to follow:
Parboil the Green Beans
Trim the ends of the green beans. Then, use a sharp knife to cut them into 2-inch pieces. This ensures even cooking and makes it easy to eat.
Bring a large pot of water to a boil over medium-high heat. Use a slotted spoon to carefully add the green beans.
Allow the vegetables to cook for about 4 to 5 minutes. You want them to be crispy tender so start checking around 3 minutes. Do NOT overcook them, since they will be baked, as well.
Drain the green beans into a colander into the sink.
Make the Fried Onions
Preheat the oven to 425℉ and line a baking sheet with parchment paper.
Use a sharp knife to cut an onion into thin slices. Aim for 2-inch-long pieces.
In one medium-sized, shallow bowl, add the flour. In a second bowl, whisk together the egg and milk. And finally, combine the breadcrumbs, salt, pepper, and garlic powder in a third bowl.
Work in batches with a few onions at a time. First dip them in the flour, then dredge them in the egg wash, and lastly coat the onions in the breadcrumbs.
Continue this process until all of the onions are covered.
Lay the coated onions in a single layer on the baking sheet and cook for 15 to 20 minutes. Be sure to flip them halfway through cooking so both sides get crispy.
The onions are done when they are a beautiful light-golden color.
Make the Cream of Mushroom Soup
While the onions are in the oven, add butter to a large skillet over medium heat. Toss in the mushrooms.
Sauté for 4 to 5 minutes, stirring along the way. Once the mushrooms are softened, add the minced garlic and continue cooking for another 30 seconds.
Sprinkle the flour over the mushrooms and garlic and stir until it is thickened.
Immediately, pour the broth into the skillet ¼-cup at a time. Use a whisk to thoroughly mix after each addition. Be sure the sauce is thickened before you stir in more broth.
After all of the broth is incorporated, pour in the milk in ¼-cup increments, as well. Whisk after each addition, waiting for it to thicken before blending in more.
Once all of the liquid is in the soup mixture, season it with salt, pepper, and dried thyme.
Put it Together
Spray a 9×13-inch baking dish with oil.
Add the green beans to the skillet with the mushroom soup. Stir well until everything is coated.
Pour the green beans into the baking dish, then top with the fried onions.
Reduce the oven temperature to 400℉. Bake the casserole uncovered for 15 to 20 minutes.
Be sure to let it rest for 10 minutes before serving.
Meal Prep Directions
There are many ways to save some time when it comes to this dish.
- You can parboil the green beans 1 to 2 days ahead of time.
- Make the cream of mushroom soup and store it in the fridge.
- Bake the onion slices.
If you prefer, you can make this casserole in its entirety the day before serving. Cover it tightly and keep it in the refrigerator. Be sure to let it come to room temperature for an hour before baking, though. Then follow the cooking instructions below.
Storage Instructions
- To Store: Keep leftover green bean casserole in an airtight container in the fridge for up to 4 to 5 days.
- To Freeze: It is best to freeze this recipe without the fried onions. Tightly wrap the dish and freeze for up to 3 to 4 months.
- To Reheat: The most suitable way to reheat already cooked green bean casserole is to return it to a 350℉ oven for 15-20 minutes, or until it is heated through.
Dietary Modifications
The recipe you’ll find below is already low-fat as written. Here are some adjustments and substitutions you can make to help it fit your other dietary requirements:
- Gluten-free: Opt for a gluten-free breadcrumbs and a 1-to-1 blend instead of all-purpose flour.
- Dairy-free: Use a plant-based milk and coconut oil rather than butter.
- Vegetarian: Replace the eggs with an alternative, like flax eggs.
FAQs
Green beans and string beans are the same! The different name comes from the silky strings that grow with the beans.
First, be sure you thicken the cream of mushroom soup enough. If it is too loose, then the casserole will be soggy. Also, do not add the onions until just before baking.
Yes! You can make your own fried onions, and they are more flavorful and healthier! Simply dredge sliced onions in flour, egg wash, and breadcrumbs, then bake in the oven until they’re crispy.
You can absolutely make the casserole a day early to save time. Be sure to let it sit at room temperature for an hour before baking.
Expert Tips and Tricks
- Short and sweet. Trim the green beans to 2 inches before cooking.
- Not too long. Only boil the green beans for a few minutes so they don’t get overcooked.
- Warm it up. Be sure the broth is warm before adding it to the flour and mushroom, so the base isn’t lumpy.
- Fatty is good. Full-fat milk adds a rich creaminess to the soup.
- Become a prepper. It is so easy to whip up this casserole a day early and simply bake it when you’re ready.
Other Green Bean Recipes
Green beans are super healthy and can be enjoyed in SO many ways, like any of these recipes:
- Green Beans Almondine with Garlic
- Sautéed Green Beans
- How to Boil Green Beans
- 15-Minute Green Beans with Vinegar
More Thanksgiving Side Dish Recipes
Thanksgiving is all about the sides… Be sure to put these on your menu this year:
- Sweet Potato Casserole
- Cajun Cornbread Dressing with Sausage
- Duchess Potatoes
- Instant Pot Mashed Potatoes
- Shaved Brussels Sprouts Salad
- Cranberry Sauce
- Roasted Garlic Mashed Cauliflower
- Mashed Sweet Potatoes
- Roasted Butternut Squash
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Ingredients
Green Beans:
- 24 oz. green beans ends trimmed, cut into 2-inch pieces
Fried Onions:
- 1 sweet onion thinly sliced
- ½ cup flour all purpose or gluten-free 1-to-1 blend
- 1 cup breadcrumbs plain, gluten-free if needed
- ½ tsp. salt
- ¼ tsp. black pepper
- ½ tsp. garlic powder
- 1 egg whisked
- 1 Tbsp. milk
Cream of Mushroom:
- 2 Tbsp. butter
- 8 oz. mushrooms coarsely chopped
- 3 cloves garlic finely minced
- 3 Tbsp. flour all purpose or gluten-free 1-to-1 blend
- ½ cup vegetable broth regular sodium
- 1-1 ¼ cups milk regular or plant-based
- 1 ¼ tsp. salt to taste
- ½ tsp. black pepper
- ½ tsp. dried thyme
Instructions
- Green Beans:
- Trim the ends of the beans and then cut into 2-inch long pieces.
- Bring a large pot of water to a boil. Carefully add the green beans to the water using a slotted spoon and boil for about 4-5 minutes, or until crisp tender. Begin checking on them after 3 minutes to ensure they do not overcook. Drain the green beans in a colander in the sink.
- Fried Onions:
- Preheat the oven to 425 degrees.
- Cut the onion into thin slices that are 2-inches long.
- Add flour to one medium-sized shallow bow. Whisk together the egg and milk in a second shallow bowl. Mix the breadcrumbs, salt, pepper, and garlic powder in a third shallow bowl.
- Dip a few of the onion strips in the flour, dredge in the egg wash, and then coat with the breadcrumbs. Lay them on a parchment paper lined baking sheet and repeat this until all of the onion pieces are completely covered.
- Bake in the preheated oven for 15-20 minutes, flipping halfway through. They should be lightly golden and crispy when done.
- Cream of Mushroom:
- While the onions are cooking, add the butter to a large skillet over medium heat along with the mushrooms. Saute for 4-5 minutes, or until softened. Add the minced garlic and continue sauteing for 30 seconds, or until fragrant.
- Sprinkle in flour and stir until thickened. Immediately begin pouring in the broth in ¼-cup increments, whisking well after each addition. Wait until the sauce has thickened up to add in the next amount. Once all of the broth has been added, pour in the milk in ¼-cup increments as well, whisking and waiting for it to thicken after each time.
- Season the cream of mushroom soup with the salt, pepper, and dried thyme.
- Add the boiled and drained green beans to the skillet and toss until they are well coated.
- Spray a 13×9-inch baking dish with non-stick cooking spray and pour in the green beans. Sprinkle the fried onions on top.
- Reduce the oven temperature to 400 degrees and bake for 15-20 minutes. Let sit at room temperature for 10 minutes before serving. Enjoy!
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Video
Notes
Storage Instructions
- To Store: Keep leftover green bean casserole in an airtight container in the fridge for up to 4 to 5 days.
- To Freeze: It is best to freeze this recipe without the fried onions. Tightly wrap the dish and freeze for up to 3 to 4 months.
- To Reheat: The most suitable way to reheat already cooked green bean casserole is to return it to a 350℉ oven for 15-20 minutes, or until it is heated through.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Hi, I don’t see mushrooms in the ingredient list- how much should I buy? When do I add it in the steps of cream of mushroom soup for the printed list? If I can’t eat nuts or soy, what can I sub for almond meal and almond/cashew/soy milk? Thanks
Hi Naomi! Thanks so much for the questions. The mushrooms are in the recipe now! So sorry for the confusion. As far as substituting for the nuts… you can try cassava flour (or regular GF flour if you are not grain-free) and use oat milk (or regular milk if you’re not DF) for the cream of mushroom soup! Would love to know what you think if you try it out 🙂
Thank you so much! I am on a migraine relief plan diet and am so grateful for your website. I have made a lot of yummy things that follow the plan, or are easily modified. (In a nutshell the diet does not allow gluten, nuts, citrus, soy, excess salt, most cheeses, sugar, onions, MSG, lentils, yogurt, vinegar, caffeine, oil except EVOO or coconut). So, thank you!
Hi Naomi! Wow!! How is the diet going for you? I suffer from migraines on a regular basis, as well. Honestly, it was one of the main reasons I started eating gluten-free and cleaning up my diet. I am SO happy you are able to find recipes that work for you. I will be sure to keep your restrictions in mind and create more recipes that work for you 🙂 Thanks so much for your kind comment!
Looks amazing and such a classic only looks way better than than many I’ve seen I love the ratio of green beans in here!!
Thanks so much, Sarah! Yes… definitely loaded it up on the green beans in this casserole 🙂