Best-Ever Green Bean Casserole Recipe

Introduction

This Best-Ever Green Bean Casserole elevates a classic side dish with fresh green beans, rich mushroom sauce, and a crispy fried onion topping. It’s creamy, flavorful, and perfect for family dinners or holiday feasts.

Ingredients

• 2 lb. fresh green beans
• Kosher salt
• 2 Tbsp. extra-virgin olive oil, divided
• 1 lb. crimini mushrooms, sliced, divided
• 6 Tbsp. unsalted butter, divided
• 4 large sprigs thyme, divided
• 2 Tbsp. all-purpose flour
• 1¼ cups whole milk
• 1 cup heavy cream
• 4 garlic cloves, finely grated
• ½ cup grated Parmesan
• Freshly ground black pepper
• ¾ cup French’s fried onions

Instructions

1. Step 1: Place a rack in the middle of the oven and preheat to 375°F (190°C). Bring a large pot of salted water to a boil. Working in batches, cook the green beans until bright green and halfway tender, about 3 minutes per batch. Drain and let cool, then trim the stem ends.
2. Step 2: Heat 1 Tbsp. olive oil in a large skillet over medium-high heat. Add half of the sliced mushrooms and cook undisturbed until golden on the bottom, about 2 minutes. Toss and cook, tossing occasionally, until browned on both sides, about 3 more minutes. Add 2 Tbsp. butter and 2 thyme sprigs, cooking until butter browns and mushrooms turn very tender, about 4 minutes. Season with kosher salt, then transfer to a plate. Repeat with remaining butter, olive oil, mushrooms, and thyme.
3. Step 3: Melt the remaining 2 Tbsp. butter in a saucepan over medium-low heat. Whisk in the flour and cook, stirring occasionally, until golden brown and fragrant, about 4 minutes. Gradually whisk in the milk and cream. Increase heat and bring to a simmer, whisking often, until sauce thickens and bubbles, about 5 minutes. Remove from heat, whisk in grated garlic, Parmesan, and season with salt and pepper.
4. Step 4: In a 2-quart baking dish, arrange the green beans and mushrooms. Pour the sauce evenly over the mixture. Cover tightly with foil and bake until bubbling, 25–30 minutes. Remove foil and bake until lightly browned on top and edges, 15–20 minutes more. Sprinkle with fried onions and bake until they darken slightly and smell fragrant, about 3 minutes. Let sit 10 minutes before serving to set.

Tips & Variations

• For extra flavor, add a splash of white wine to the mushrooms while sautéing.
• Substitute Gruyère or sharp cheddar for Parmesan for a different cheesy twist.
• Fresh thyme can be replaced with rosemary or sage for an herbal variation.
• If you prefer a lighter dish, use half-and-half instead of cream.

Storage

Store leftovers covered in the refrigerator for up to 3 days. To reheat, warm gently in the oven at 350°F (175°C) until heated through to keep the topping crisp. Avoid microwaving to maintain texture.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I use frozen green beans instead of fresh?

Fresh green beans provide the best texture and flavor, but if you use frozen, thaw and drain them well, then reduce the initial boiling time to avoid overcooking.

What can I substitute for French’s fried onions?

You can use homemade crispy fried shallots, crushed crispy fried garlic, or even toasted breadcrumbs for a crunchy topping if French’s fried onions are unavailable.

Best-Ever Green Bean Casserole Recipe

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★★★★★

4.5 from 163 reviews

This Best-Ever Green Bean Casserole is a delicious twist on the classic dish, featuring fresh green beans, sautéed crimini mushrooms, and a rich, creamy béchamel sauce infused with garlic and Parmesan. Topped with crispy French’s fried onions, this casserole is perfect for holiday dinners or comforting family meals.

• Author: Rita
• Prep Time: 20 minutes
• Cook Time: 1 hour
• Total Time: 1 hour 20 minutes
• Yield: 6 servings 1x
• Category: Side Dish
• Method: Baking
• Cuisine: American

Ingredients

Scale 1x2x3x

Vegetables & Herbs

• 2 lb. fresh green beans
• 1 lb. crimini mushrooms, sliced
• 4 large sprigs thyme

Fats & Oils

• 2 Tbsp. extra-virgin olive oil, divided
• 6 Tbsp. unsalted butter, divided

Dairy

• 1¼ cups whole milk
• 1 cup heavy cream
• ½ cup grated Parmesan

Other

• Kosher salt
• 2 Tbsp. all-purpose flour
• 4 garlic cloves, finely grated
• Freshly ground black pepper
• ¾ cup French’s fried onions

Instructions

1. Blanch Green Beans: Place a rack in the middle of the oven and preheat to 375°F. Boil a large pot of salted water. Working in batches, cook 2 lb. fresh green beans until bright green and halfway tender, about 3 minutes per batch. Drain, let cool slightly, and trim the stem ends.
2. Sauté Mushrooms – First Batch: Heat 1 Tbsp. extra-virgin olive oil in a large skillet over medium-high heat. Add ½ lb. sliced crimini mushrooms and cook without stirring for 2 minutes to brown the undersides. Toss and continue cooking until both sides are browned, about 3 minutes more. Add 2 Tbsp. unsalted butter and 2 large thyme sprigs; cook, tossing occasionally, until butter browns and mushrooms are very tender, approximately 4 minutes. Season with kosher salt and transfer to a plate.
3. Sauté Mushrooms – Second Batch: Repeat the mushroom cooking process with the remaining ½ lb. mushrooms, 2 Tbsp. unsalted butter, 1 Tbsp. extra-virgin olive oil, salt, and the remaining 2 large thyme sprigs, until browned and tender.
4. Make Béchamel Sauce: Melt remaining 2 Tbsp. unsalted butter in a large saucepan over medium-low heat. Whisk in 2 Tbsp. flour and cook, stirring occasionally, until roux is golden brown and fragrant, about 4 minutes. Gradually whisk in 1¼ cups whole milk and 1 cup heavy cream. Increase heat to bring mixture to a simmer; cook and whisk often until sauce thickens and bubbles, about 5 minutes. Remove from heat and whisk in finely grated 4 garlic cloves and ½ cup Parmesan cheese. Season with salt and freshly ground black pepper to taste.
5. Assemble and Bake Casserole: In a 2-quart baking dish, arrange blanched green beans and sautéed mushrooms. Pour the béchamel sauce evenly over the vegetable mixture; it may seem sparse but will become saucier during baking. Cover tightly with foil and bake for 25–30 minutes until sauce bubbles.
6. Brown Topping: Remove foil and continue baking for 15–20 minutes more, until casserole is lightly browned on top and edges. Sprinkle ¾ cup French’s fried onions evenly over casserole and bake an additional 3 minutes until onions are slightly darker and fragrant.
7. Rest and Serve: Let casserole sit for 10 minutes to set before serving, allowing flavors to meld and sauce to thicken.

Notes

• Blanching the green beans before baking ensures they stay crisp-tender and vibrant in color.
• Sauté mushrooms in batches without stirring initially to get a nice golden sear and deepen flavor.
• Béchamel sauce made with garlic and Parmesan adds rich flavor and creaminess.
• Covering the casserole with foil prevents drying during initial baking, while uncovering allows browning.
• French’s fried onions provide traditional crispy topping and texture contrast.
• Allowing the casserole to rest after baking helps the sauce to thicken and the dish to set for easier serving.

Keywords: green bean casserole, mushroom casserole, holiday side dish, creamy green beans, baked green beans, French fried onions, Thanksgiving side