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A casserole dish full of homemade green bean casserole.
5 from 4 votes

Green Bean Casserole from Scratch

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.

Course Dinner, Side Dish
Cuisine American
Prep Time 30 minutes
Cook Time 30 minutes
Total Time 1 hour
Servings 8 servings
Calories 177 kcal


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


  1. Green Beans:
  2. Trim the ends of the beans and then cut into 2-inch long pieces.
  3. 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.
  4. Fried Onions:
  5. Preheat the oven to 425 degrees.

  6. Cut the onion into thin slices that are 2-inches long.
  7. 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.
  8. 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.
  9. Bake in the preheated oven for 15-20 minutes, flipping halfway through. They should be lightly golden and crispy when done.
  10. Cream of Mushroom:
  11. 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.
  12. 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.
  13. Season the cream of mushroom soup with the salt, pepper, and dried thyme.
  14. Add the boiled and drained green beans to the skillet and toss until they are well coated.
  15. Spray a 13x9-inch baking dish with non-stick cooking spray and pour in the green beans. Sprinkle the fried onions on top.
  16. Reduce the oven temperature to 400 degrees and bake for 15-20 minutes. Let sit at room temperature for 10 minutes before serving. Enjoy!

Recipe Video

Recipe 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 Facts
Green Bean Casserole from Scratch
Amount Per Serving
Calories 177 Calories from Fat 45
% Daily Value*
Fat 5g8%
Saturated Fat 2g13%
Trans Fat 0.1g
Polyunsaturated Fat 1g
Monounsaturated Fat 1g
Cholesterol 28mg9%
Sodium 641mg28%
Potassium 342mg10%
Carbohydrates 28g9%
Fiber 5g21%
Sugar 5g6%
Protein 7g14%
Vitamin A 755IU15%
Vitamin C 12mg15%
Calcium 83mg8%
Iron 3mg17%
* Percent Daily Values are based on a 2000 calorie diet.