green bean casserole from scratch uses fresh green beans and a homemade mushroom sauce instead of canned condensed soup. It keeps the comforting holiday flavor people expect while adding a brighter vegetable texture and a richly savory sauce.
This recipe is practical for Thanksgiving because the beans and sauce can be prepared ahead. The key is to blanch the beans briefly, then finish the casserole in the oven. That prevents them from turning mushy while the sauce bubbles.
Why You Will Love This green bean casserole from scratch
Mushrooms bring savory depth, flour lightly thickens the milk-and-broth sauce, and crisp fried onions supply the classic crunchy topping. You do not need fancy ingredients or unusual equipment—just a skillet, a pot and a baking dish.
Green Bean Casserole From Scratch with Mushrooms: Ingredients and Timing
Yield: 8 side servings. Prep: 25 minutes. Cook: 30 minutes. Oven: 375°F (190°C).
Ingredients
- 1½ lb (680 g) fresh green beans, trimmed
- 12 oz (340 g) cremini mushrooms, sliced
- 3 tablespoons unsalted butter
- 1 small yellow onion, finely diced
- 2 garlic cloves, minced
- 3 tablespoons all-purpose flour
- 1 cup low-sodium vegetable or chicken broth
- 1 cup whole milk
- ½ teaspoon dried thyme
- ¾ teaspoon kosher salt, or to taste
- ½ teaspoon freshly ground black pepper
- 1 teaspoon Dijon mustard, optional
- 1½ cups store-bought crispy fried onions, divided
How to Make green bean casserole from scratch
- Blanch the green beans. Bring a large pot of salted water to a boil. Add green beans and cook 3–4 minutes until bright green and barely tender. Transfer immediately to a bowl of ice water; drain and pat dry.
- Brown the mushrooms. Heat a large skillet over medium-high heat. Melt butter, add mushrooms and cook about 6–8 minutes until their moisture evaporates and edges begin to brown.
- Build the flavor. Reduce heat to medium, add diced onion and cook 3–4 minutes until softened. Add garlic and cook for 30 seconds, stirring to prevent scorching.
- Make the sauce. Sprinkle flour over the vegetables and stir for one minute. Gradually whisk in broth and milk. Add thyme, salt, pepper and mustard. Simmer 4–6 minutes until the sauce lightly coats a spoon.
- Combine. Heat oven to 375°F (190°C). Fold the drained green beans and ½ cup fried onions into the mushroom sauce. Transfer to a greased 2½- to 3-quart baking dish.
- Bake. Bake uncovered 20 minutes until bubbling. Scatter the remaining 1 cup fried onions across the top and bake 5–8 minutes more, just until crisp and golden. Rest five minutes before serving.
Tips for a Better Result
- Dry the beans well: Excess water is the main reason a scratch-made casserole gets thin.
- Brown mushrooms properly: Let them cook before adding salt-heavy liquid; this deepens their flavor.
- Do not add all the onions early: Most of the crispy onions should go on during the final minutes so they do not become soggy.
- Check sauce consistency: The sauce should be slightly thicker than cream before baking because the beans release a little moisture.
Easy Variations
For a richer result, swap ½ cup of the milk for half-and-half. For a vegetarian casserole use vegetable broth. A small pinch of smoked paprika adds warmth, but keep it subtle so the mushrooms remain the main flavor.
What to Serve With It
This green bean casserole from scratch works alongside roast chicken, turkey, or prime rib. For more holiday pairings see our Christmas side dishes and garlic butter prime rib.
Make-Ahead and Storage
Make ahead
Blanch and dry the beans and cook the mushroom sauce up to one day ahead. Refrigerate separately or combine in the baking dish. Add a splash of milk if the chilled sauce has thickened, and add the crispy topping only during the final bake.
Leftovers
Refrigerate leftovers within two hours for up to 3–4 days. Reheat until steaming hot; add extra crispy onions after reheating if desired. Freezing is possible, but the creamy sauce can change texture when thawed.
green bean casserole from scratch FAQ
Can I use frozen green beans?
Yes. Thaw and drain very thoroughly, and skip the full blanching step. They may be softer than fresh beans.
Can I make this without mushroom soup?
Yes—this recipe uses a simple homemade sauce made with butter, flour, milk, broth and mushrooms.
How do I prevent watery casserole?
Dry the blanched beans, cook moisture out of the mushrooms and simmer the sauce until lightly thickened.
Can I make it the day before?
Yes, assemble without the final onion topping, refrigerate and bake the next day.
Save This Recipe for Your Holiday Menu
green bean casserole from scratch is worth keeping for busy holiday entertaining. Save these instructions, check the ingredient list before shopping, and share the recipe with someone planning their next family meal.
