Name: Best Green Bean Casserole from Scratch
Prep time: 5 min
Cook time: 40 min
Total time: 45 min
Cuisine: American
Ingredients: 1 lb fresh or frozen green beans; 3 tablespoons butter; ½ medium onion, chopped; 10 oz fresh sliced mushrooms (cleaned); ½ teaspoon garlic powder; Salt and pepper, to taste; ⅓ cup all-purpose flour; ½ cup half and half; 1½ cups whole milk; 1 cup French’s Crispy Fried Onions

Why You’ll Love This Recipe

I love how this casserole skips the canned soup without sacrificing the classic taste. It uses simple, fresh ingredients and turns them into something that feels both nostalgic and elevated. The homemade mushroom sauce is rich and creamy, the green beans keep their texture, and those crispy onions on top bring the perfect crunch. Whether it’s for Thanksgiving or a comforting Sunday dinner, this is always a hit at my table.

Ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

1 lb fresh or frozen green beans
1/2 cup half and half
1 1/2 cups whole milk
1/3 cup flour
3 tablespoons butter
1/2 medium onion, chopped
10 oz fresh sliced mushrooms
1/2 teaspoon garlic powder
Salt and pepper, to taste
1 cup French’s Crispy Fried Onions

Directions

I begin by preheating my oven to 350°F (176°C). Then I cook the green beans on high heat for about 10 minutes until just tender. I drain them and set them aside.

In a large skillet over medium heat, I melt the butter and add the chopped onions, mushrooms, garlic powder, salt, and pepper. I cook everything for about 5 minutes, stirring occasionally.

To make the creamy sauce, I sift in the flour one tablespoon at a time, alternating with small splashes of half and half and milk. I stir constantly to avoid any lumps, continuing to add flour and liquid gradually until everything is fully incorporated into a thick, smooth sauce. (I never dump all the flour in at once—it’ll turn pasty.)

Once the sauce is ready, I remove it from the heat and stir in the cooked green beans. I transfer the mixture into a 7″x 3″x 11″ baking dish and bake uncovered for 30 minutes.

After that, I sprinkle the crispy fried onions over the top and return the dish to the oven for another 5 minutes until the onions are golden and crisp.

Servings and timing

This recipe makes 6 servings and takes a total of 45 minutes—5 minutes to prep, 10 minutes to cook the green beans and sauce, and 30 minutes to bake. It’s the perfect side for Thanksgiving, Christmas, or any meal where I want to serve something cozy and classic.

Variations

Add cheese: Sometimes I mix shredded cheddar or Gruyère into the sauce for an extra-rich twist.
Switch the milk: I’ve used 2% milk or even all half and half when I wanted a creamier result.
Fresh herbs: A touch of thyme or rosemary adds a lovely earthy note to the sauce.
Crunch swap: I’ve tried crushed Ritz crackers or panko in place of crispy onions for variety.
Gluten-free version: I use a gluten-free flour blend and gluten-free fried onions, and it turns out just as good.

Storage/Reheating

I store leftovers in the refrigerator, covered, for up to 5 days. It reheats well in the oven at 350°F for 15–20 minutes until hot, or in the microwave for individual portions. For longer storage, I freeze the casserole (without the crispy onions) for up to 6 months. When I’m ready to serve, I thaw it overnight in the fridge and reheat, adding fresh onions at the end to crisp up.

FAQs

Can I use canned green beans instead of fresh or frozen?

Yes, I’ve used canned in a pinch. I just make sure to drain them well and reduce the cooking time since they’re already soft.

What kind of mushrooms work best?

I typically use white button or cremini mushrooms, but any fresh variety works. I slice them thin so they cook down evenly into the sauce.

Can I make this ahead of time?

Absolutely. I assemble the casserole (without the fried onions), cover it, and refrigerate it for up to 24 hours. Then I bake it and add the onions just before the final 5 minutes in the oven.

Can I double the recipe for a crowd?

Yes, doubling works great. I use a larger baking dish and increase the baking time by about 10 minutes before adding the topping.

Is there a dairy-free option?

I’ve made this with plant-based butter, almond milk, and dairy-free cream. It’s still creamy and flavorful, though the texture may vary slightly.

Conclusion

This Best Green Bean Casserole from Scratch is everything I want in a holiday side dish—classic, creamy, and full of fresh, homemade flavor. With tender green beans, rich mushroom sauce, and that irresistible crispy topping, it never lasts long at the table. Once I started making it this way, I never went back to the canned version.