Classic Green Bean Casserole

Featured in: Oven & Skillet Meals

This beloved comfort dish features fresh green beans swimming in a velvety homemade mushroom sauce made with butter, garlic, and a hint of nutmeg. The crowning glory is a generous layer of crispy fried onions that turn golden and bubbly in the oven. Ready in under an hour, this casserole serves six perfectly and can be assembled ahead of time for stress-free entertaining.

Updated on Tue, 13 Jan 2026 11:07:00 GMT
Green Bean Casserole with tender green beans in creamy mushroom sauce, topped with golden crispy onions in a white baking dish. Save
Green Bean Casserole with tender green beans in creamy mushroom sauce, topped with golden crispy onions in a white baking dish. | goldentalaxt.com

The smell of crispy fried onions baking has become my personal signal that the holidays have officially begun. I stumbled upon making green bean casserole from scratch during one particularly chaotic Thanksgiving when my sister announced she had gone vegetarian, and suddenly the traditional cream-of-mushroom soup version felt like it needed an upgrade. The first batch I made had sauce that refused to thicken, leading to a frantic phone call with my grandmother at midnight while I whisked furiously. Now it is the one dish my family actually requests weeks in advance, and there is something deeply satisfying about transforming humble green beans into something that disappears within minutes.

Last December, I brought this to a potluck where the host confessed she had spent years hiding green bean casserole in her napkin. Watching her go back for thirds and then ask for the recipe might be one of my proudest kitchen moments. My niece who normally will not touch anything green helped herself to the biggest portion at the table, proving that sometimes the side dishes become the unexpected stars.

Ingredients

  • Fresh green beans: I learned the hard way that frozen ones turn mushy, though they work in a pinch if thawed thoroughly first
  • Cremini mushrooms: These have more flavor than white button mushrooms and hold their texture better in the sauce
  • Sour cream: This was my secret discovery for adding tang and richness without making the sauce too heavy
  • Fried onions: Homemade ones are incredible but store bought ones absolutely work when time is short
  • Nutmeg: Just a pinch adds this subtle warmth that people cannot quite put their finger on but definitely notice

Instructions

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Blanch the beans:
Drop them into boiling salted water just until they turn bright green, then immediately shock them in ice water. This step preserves that fresh snap texture that makes all the difference.
Build the flavor base:
Sauté your onions and mushrooms until the mushrooms release all their liquid and start to brown. You want them deeply golden so the sauce has that rich mushroom intensity.
Make the sauce:
Stir in the flour and let it cook briefly before gradually whisking in the liquids. The sauce should coat the back of a spoon and look silky and thick.
Combine and bake:
Fold the beans into the sauce and top with most of the onions. The first bake gets everything bubbling, then add the remaining onions for that final golden crunch.
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Boil water quickly for tea, coffee, instant soups, and faster prep when cooking grains or noodles.
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Homemade Green Bean Casserole in a skillet, featuring sautéed mushrooms, fresh green beans, and rich creamy sauce ready to bake. Save
Homemade Green Bean Casserole in a skillet, featuring sautéed mushrooms, fresh green beans, and rich creamy sauce ready to bake. | goldentalaxt.com

There is something about the bubbling sound this casserole makes when it comes out of the oven that makes everyone drift toward the kitchen. My dad now stands by the oven door waiting for those final five minutes, claiming he needs to check something but really just wants first access to the crispy topping.

Make It Your Own

I have experimented with adding a splash of dry sherry to the sauce, which gives it this sophisticated depth nobody expects. A handful of shredded gruyère folded into the sauce makes it incredibly decadent, though the purists in my family prefer the classic version.

Timing Secrets

This dish can be assembled completely up to 24 hours ahead, just wait to add the fried onions until you bake. I have found it actually tastes better this way since the flavors have time to meld together in the refrigerator.

Serving Ideas

While it is perfect alongside holiday roasts, this also works beautifully as part of a vegetarian main spread. The first time I served it with vegetarian lasagna, my brother admitted he actually preferred the casserole.

  • Try it with roasted sweet potatoes for a colorful holiday plate
  • A crisp green salad with vinaigrette cuts through the richness nicely
  • Leftovers reheat surprisingly well in the oven if you have any
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Festive Green Bean Casserole served as a side dish with crispy fried onion topping, perfect for Thanksgiving dinner or family meals. Save
Festive Green Bean Casserole served as a side dish with crispy fried onion topping, perfect for Thanksgiving dinner or family meals. | goldentalaxt.com

Every time I pull this out of the oven now, I think about how far I have come from that frantic Thanksgiving night. Some dishes really do get better with time and practice.

Recipe FAQs

Can I make this ahead of time?

Yes! Assemble the casserole without the fried onion topping, cover tightly, and refrigerate for up to 24 hours. Add the crispy onions just before baking.

Can I use frozen green beans?

Absolutely. Thaw frozen green beans completely and skip the initial blanching step since they're already partially cooked during processing.

How do I make this gluten-free?

Replace all-purpose flour with a 1:1 gluten-free flour blend and ensure your fried onions are certified gluten-free or make them with gluten-free breadcrumbs.

Can I substitute the fresh mushrooms?

You can use canned mushroom pieces or omit mushrooms entirely. For a similar umami flavor, add a splash of soy sauce to the sauce mixture.

How long does this reheat well?

Leftovers keep refrigerated for 3-4 days. Reheat covered at 350°F (175°C) for 15-20 minutes until heated through. The crispy topping may soften slightly.

Can I freeze this casserole?

Freezing works best before baking. Assemble without the onion topping, wrap tightly, and freeze for up to 2 months. Thaw overnight in refrigerator before baking with fresh onions.

Classic Green Bean Casserole

Tender green beans in creamy mushroom sauce with crispy onion topping

Prep time
15 minutes
Cook duration
35 minutes
Overall time
50 minutes
Written by Trevor DeLaCruz


Skill level Easy

Cuisine type American

Total yield 6 Portions

Dietary info Vegetarian-friendly

What you'll need

Vegetables

01 1 lb fresh green beans, trimmed and cut into 2-inch pieces
02 1 small yellow onion, finely chopped
03 2 cloves garlic, minced
04 8 oz cremini or button mushrooms, sliced

Sauce

01 2 tbsp unsalted butter
02 2 tbsp all-purpose flour
03 1 cup whole milk
04 1/2 cup low-sodium vegetable broth
05 1/2 cup sour cream
06 1/2 tsp salt
07 1/4 tsp black pepper
08 1/4 tsp ground nutmeg

Topping

01 1 1/2 cups crispy fried onions

How to make it

Step 01

Preheat Oven: Preheat oven to 350°F.

Step 02

Blanch Green Beans: Bring a large pot of salted water to a boil. Add green beans and cook for 4–5 minutes until bright green and just tender. Drain and immediately transfer to a bowl of ice water to stop the cooking. Drain again and set aside.

Step 03

Sauté Aromatics: In a large skillet over medium heat, melt butter. Add chopped onion and cook for 2–3 minutes until softened. Add garlic and mushrooms; cook for another 5 minutes until mushrooms are tender and any liquid has evaporated.

Step 04

Prepare Sauce Base: Stir in flour and cook for 1 minute, stirring constantly. Gradually whisk in milk and vegetable broth. Cook, stirring, until sauce thickens, about 3–4 minutes.

Step 05

Season Sauce: Remove skillet from heat. Stir in sour cream, salt, pepper, and nutmeg until smooth.

Step 06

Combine Beans and Sauce: Add drained green beans to the sauce and mix to coat evenly.

Step 07

Assemble Casserole: Transfer mixture to a greased 2-quart baking dish. Sprinkle 1 cup of crispy fried onions evenly over the top.

Step 08

Initial Bake: Bake for 25 minutes until bubbling. Remove from oven, top with remaining crispy onions, and bake an additional 5 minutes until golden brown.

Step 09

Rest Before Serving: Let rest for 5 minutes before serving.

Gear needed

  • Large pot
  • Large skillet
  • Mixing bowls
  • Whisk
  • 2-quart baking dish
  • Strainer

Allergy details

Look over each item for allergens. If not sure, always talk to your healthcare provider.
  • Contains dairy (butter, milk, sour cream)
  • Contains wheat/gluten (flour, fried onions)

Nutrition info (one serving)

For your general understanding only. Medical advice should always come from health professionals.
  • Energy: 210
  • Fat content: 12 g
  • Carbohydrates: 21 g
  • Proteins: 5 g