Green Bean Casserole with Mushrooms & Garlic

Photo of author
Author: Natalie
Published:
Green bean casserole featuring sautéed mushrooms and garlic sauce.

Why This Version Stands Out

Typical green bean casseroles are creamy and comforting but often mild. By leaning into sautéed mushrooms and roasted or caramelized garlic, this version adds depth, earthiness, and savory complexity. You’ll taste the mushrooms’ umami, the garlic’s warmth, and the green beans’ brightness — all balanced in a creamy sauce. The crispy onion topping (optional) adds that familiar crunch, but this dish shines even without overdoing textures.


Ingredients & Tools You’ll Need

Ingredients (serves 6–8)

  • 1½ to 2 lbs fresh green beans, trimmed and cut into bite‑size pieces

  • 2 tablespoons butter (or olive oil, or a mix)

  • 1 medium onion, finely diced

  • 10–12 oz mushrooms (button, cremini, or mixed), sliced

  • 3–4 cloves garlic, minced (or roasted garlic for mellower flavor)

  • 2 tablespoons all-purpose flour

  • 1 to 1¼ cups milk (whole milk or a mix of milk + cream)

  • ½ cup broth (vegetable or chicken)

  • ½ teaspoon dried thyme (or fresh)

  • Salt and freshly ground black pepper

  • 1 to 1¼ cups crispy fried onions (store-bought or homemade) — optional or partial

  • Fresh parsley or chives for garnish

Tools & Equipment

  • Large pot or saucepan for blanching

  • Skillet or sauté pan

  • Baking dish (~9×13 or similar)

  • Mixing bowls

  • Whisk, spatula, spoon

  • Knife, cutting board

  • Oven preheating


Step‑by‑Step Instructions

1. Preheat & Prepare Beans

Preheat oven to 375 °F (190 °C).

Trim ends off the green beans and cut into ~1–1.5 inch segments. Bring a large pot of salted water to a boil. Blanch the beans 3–4 minutes (just until bright green, still a little crisp). Drain and optionally plunge into cold water to stop cooking and preserve color. Drain thoroughly.

Blanching helps ensure green beans don’t become mushy during casserole baking.

2. Sauté Onion, Mushrooms & Garlic

In a skillet over medium heat, melt butter (or warm oil). Add the diced onion and cook until translucent (4–5 minutes). Add mushrooms and sauté until they release moisture and begin to brown (5–7 minutes). Add garlic and cook about 30 seconds more, being careful not to burn. If using roasted garlic instead, stir it in near the end for mellow flavor.

This develops savory layers before the sauce.

3. Build the Sauce

Sprinkle the flour over the onion–mushroom–garlic mixture, stirring to coat. Cook ~1 minute to eliminate raw flour taste. Gradually whisk in milk and broth, stirring constantly to avoid lumps. Bring to a simmer, allow to thicken (2–4 minutes). Stir in thyme, salt, and pepper to taste.

If desired, you may stir in ½ cup of cheese (cheddar, Gruyère) for additional richness.

4. Combine Beans & Sauce, Add Onion Crunch

Gently fold the blanched beans into this creamy mushroom-garlic sauce until well coated. For extra onion flavor inside, fold in half of your crispy fried onions (optional). This ensures that some crunch is embedded inside, not just on top.

5. Transfer & Top

Transfer the bean + sauce mix into your greased baking dish, spreading evenly. Sprinkle the remaining crispy fried onions over the top. If the topping seems dry, you can drizzle a little melted butter or cream to encourage browning.

6. Bake

Bake uncovered for 25–30 minutes, until sauce bubbles and edges look set. If the topping isn’t golden enough, switch to broiler for 1–2 minutes (watch carefully) to crisp the onions.

7. Rest, Garnish & Serve

Let the casserole rest for 5–10 minutes so the sauce firms slightly, making it easier to serve. Garnish with chopped fresh parsley or chives before serving.


Tips & Flavor Enhancements

  • Roasted garlic: Roast whole garlic cloves ahead, mash, and stir into sauce for a mellow, rich garlic flavor.

  • Mushroom variety: Use cremini, shiitake, or a wild mushroom mix to deepen umami.

  • Less topping, more flavor: You don’t need a huge onion topping; subtle amounts suffice when your sauce is flavorful.

  • Cheese layer: A light layer of melting cheese just under the topping gives extra richness.

  • Make it ahead: Assemble (beans + sauce) and refrigerate covered, up to 24 hours. Top with onions just before baking.

  • Adjust texture: If you like your green beans firmer, reduce blanch time. If softer, bake a bit longer.


Serving & Pairing Suggestions

Serve this as a standout side with:

  • Roast turkey or chicken

  • Mashed potatoes

  • Stuffing

  • Cranberry sauce

  • Roasted root vegetables

  • Dinner rolls

Because it’s rich, include a crisp or acidic side (e.g. a green salad with vinaigrette) to balance.


Storage & Reheating

  • Leftovers: Store in airtight container in refrigerator for 3–4 days.

  • Reheat: Warm in oven at ~325 °F (160 °C) until hot, uncovered to preserve occasional crispness.

  • Refresh topping: If topping softens, sprinkle fresh onions or broil briefly before serving.


Nutritional & Health Notes

  • This recipe emphasizes vegetables and controlled dairy; you can lighten by reducing butter or using lower-fat milk.

  • Mushrooms and garlic bring nutrients and antioxidants.

  • By embedding some crispy onions rather than overloading the top, you moderate added fat or oil.


Frequently Asked Questions

Can I skip the crispy onions?
Yes — the dish is still excellent without them. The flavor from mushrooms and garlic carries it.

Can I use frozen or canned beans?
Yes. Thaw and drain frozen beans. For canned, drain and rinse well. Texture might be softer, but acceptable.

Can I make it vegan or dairy-free?
Yes. Use plant milk + plant-based butter or oil, and a vegan cheese or omit cheese. The method remains largely the same.

How far ahead can I prep it?
You can prepare the bean + sauce mixture and keep it refrigerated (without topping) 24 hours ahead. Then top and bake when needed.

Will the topping burn under broiler?
It can if too close or too long. Only broil 1 minute or two, and keep eye on it. Start it slightly further from heat.

Natalie, a cheerful home chef, smiling in her bright kitchen while holding a mixing bowl and spoon — perfect for EasyFoodToMake
Natalie

Welcome to Easy Food To Make! I’m Natalie, the recipe creator and food lover behind this site. Here, I share easy, delicious, and comforting recipes perfect for busy days and cozy nights. Whether you're in the mood for a quick dinner, homemade bread, or a sweet dessert, you're in the right place. Let’s make something tasty together!

Love This Recipe? Don't Lose It!

Subscribe now and Get your FREE Cookbook! 🎉 Delicious recipes are just one click away! 👩‍🍳🍽️

We use your personal data for interest-based advertising, as outlined in our Privacy Notice.

You Might Also Like...

Caprese Candy Cane Skewers

Caprese Candy Cane Skewers

Everything Seasoning Cheese Ball

Everything Seasoning Cheese Ball

Cranberry Cream Cheese Dip (Warm)

Cranberry Cream Cheese Dip (Warm)

Prosciutto Wrapped Dates with Goat Cheese

Prosciutto Wrapped Dates with Goat Cheese

Leave a Comment