I love having a creamy green bean casserole on the Thanksgiving table, especially one with tender green beans, savory mushrooms, and plenty of crisp onions on top. This from-scratch version is simple to prepare and makes a cozy side dish for sharing with family and friends.

Why You’ll Love This Green Bean Casserole

This casserole brings together fresh green beans and a creamy mushroom sauce without relying on canned soup. The crunchy onion topping adds a satisfying contrast, and you can prepare much of the dish ahead to make holiday cooking easier.

Green Bean Casserole Ingredients & Substitutions

1 ½ pounds fresh green beans, trimmed and cut into bite-size pieces
2 tablespoons unsalted butter
8 ounces cremini or button mushrooms, sliced
2 cloves garlic, minced
3 tablespoons all-purpose flour
1 cup vegetable broth
1 cup whole milk
½ teaspoon onion powder
½ teaspoon fine salt, plus more for the cooking water
¼ teaspoon black pepper
1 ½ cups crispy fried onions, divided

Cremini or button mushrooms both work well. For a richer sauce, replace some of the milk with cream. Frozen green beans can be used in a pinch; thaw and drain them well before adding to the casserole.

Step-by-Step Instructions to Make Green Bean Casserole

1. Blanch the green beans

Heat the oven to 375°F (190°C). Bring a large pot of salted water to a boil, add the green beans, and cook for 4 to 5 minutes, until bright green and just tender. Drain, then rinse briefly with cool water to stop the cooking.

2. Make the mushroom sauce

Melt the butter in a large skillet over medium heat. Add the mushrooms and cook for 6 to 8 minutes, stirring occasionally, until tender and their released liquid has mostly evaporated. Stir in the garlic and cook for 30 seconds.

3. Thicken the sauce

Sprinkle the flour over the mushrooms and stir until evenly coated. Slowly pour in the vegetable broth, stirring to smooth out any lumps, then add the milk, onion powder, salt, and pepper. Simmer for 3 to 5 minutes, stirring often, until the sauce is thick enough to coat a spoon.

4. Assemble the casserole

Stir the green beans and ½ cup of the crispy fried onions into the sauce. Transfer the mixture to a greased 2-quart baking dish and spread it into an even layer.

5. Bake and add the topping

Bake uncovered for 20 minutes. Sprinkle the remaining crispy fried onions over the top and bake for another 5 to 8 minutes, until the casserole is bubbling and the onions are golden. Let it rest for about 5 minutes before serving.

Tips for Success

Blanch the beans until just tender so they keep their shape after baking.
Let the mushrooms cook until most of their moisture has evaporated. This helps the sauce stay creamy rather than watery.
Add the final layer of crispy onions near the end of baking to help keep them crunchy.
Taste the sauce before assembling and adjust the salt and pepper to suit your preference.

Variations of Green Bean Casserole

For extra savory flavor, stir a pinch of smoked paprika into the mushroom sauce. You can also use a mix of mushrooms, such as cremini and shiitake, or add a handful of grated cheddar to the sauce. If you like a lighter topping, use toasted breadcrumbs mixed with a little melted butter in place of some of the crispy onions.

Serving Suggestions: What to Pair with Green Bean Casserole

Serve this casserole alongside roast turkey, mashed potatoes, stuffing, or glazed carrots for a classic Thanksgiving plate. It also pairs nicely with roasted squash and a crisp green salad, which balance its creamy texture.

Storage & Reheating Instructions

Cool leftovers, then store them in an airtight container in the refrigerator for up to 3 days. Reheat individual portions in the microwave, or warm the casserole in a covered baking dish at 350°F (175°C) until heated through. The onion topping is crispiest when refreshed with a few minutes in the oven uncovered.

Memories Made Around the Table

I love the moment a bubbling casserole comes out of the oven and everyone gathers around to fill their plates. The crisp onions always seem to draw people in first, while the creamy beans make this dish feel right at home beside all the other Thanksgiving favorites.

FAQs

Can I make green bean casserole ahead of time?

Yes. Prepare the green beans and mushroom sauce, combine them in the baking dish, cover, and refrigerate for up to 1 day. Bake until hot, then add the crispy onion topping near the end.

Can I use frozen green beans?

Yes. Thaw the beans completely and drain them well before stirring them into the sauce. Since frozen beans may already be soft, avoid overcooking them before baking.

How do I keep the casserole from getting watery?

Cook the mushrooms until their liquid has mostly evaporated, drain the green beans thoroughly, and simmer the sauce until it thickens before combining everything.

Can I freeze green bean casserole?

You can freeze the assembled casserole without the crispy onion topping for up to 2 months. Thaw it overnight in the refrigerator, bake until hot, then add the onions for the final few minutes.

Final Thoughts

This green bean casserole is creamy, savory, and finished with the crunch everyone looks forward to. Keep it classic for Thanksgiving or make it your own with a favorite mushroom or topping variation.

Green Bean Casserole

A from-scratch green bean casserole with tender green beans, savory mushrooms, a creamy mushroom sauce, and a crisp fried onion topping. A cozy Thanksgiving side dish that can be prepared ahead.

Print Recipe Pin Recipe

Prep Time 15

Cook Time 45

Resting Time 5

Total Time 1 5

Course Side Dish

Cuisine American

Servings 8 people

Equipment

1 Large Pot
1 Large Skillet
1 2-quart baking dish

Ingredients

1.5 pounds fresh green beans trimmed and cut into bite-size pieces
2 tablespoons unsalted butter
8 ounces cremini or button mushrooms sliced
2 cloves garlic minced
3 tablespoons all-purpose flour
1 cup vegetable broth
1 cup whole milk
0.5 teaspoon onion powder
0.5 teaspoon fine salt plus more for the cooking water
0.25 teaspoon black pepper
1.5 cups crispy fried onions divided

Instructions

Heat the oven to 375°F (190°C). Bring a large pot of salted water to a boil, add the green beans, and cook for 4 to 5 minutes, until bright green and just tender. Drain, then rinse briefly with cool water to stop the cooking.
Melt the butter in a large skillet over medium heat. Add the mushrooms and cook for 6 to 8 minutes, stirring occasionally, until tender and their released liquid has mostly evaporated. Stir in the garlic and cook for 30 seconds.
Sprinkle the flour over the mushrooms and stir until evenly coated. Slowly pour in the vegetable broth, stirring to smooth out any lumps, then add the milk, onion powder, salt, and pepper. Simmer for 3 to 5 minutes, stirring often, until the sauce is thick enough to coat a spoon.
Stir the green beans and ½ cup of the crispy fried onions into the sauce. Transfer the mixture to a greased 2-quart baking dish and spread it into an even layer.
Bake uncovered for 20 minutes. Sprinkle the remaining crispy fried onions over the top and bake for another 5 to 8 minutes, until the casserole is bubbling and the onions are golden. Let it rest for about 5 minutes before serving.

Notes

Blanch the beans until just tender and cook the mushrooms until most of their moisture has evaporated to help prevent a watery casserole. Add the final layer of crispy onions near the end of baking to keep them crunchy. To prepare ahead, combine the beans and sauce in the baking dish, cover, and refrigerate for up to 1 day; bake until hot and add the crispy onions near the end. Refrigerate leftovers in an airtight container for up to 3 days. For freezing, freeze the assembled casserole without the onion topping for up to 2 months; thaw overnight in the refrigerator before baking.