Green Bean Casserole From Scratch

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No cans here! This Homemade Green Bean Casserole is creamy, a little cheesy, and loaded with flavor—topped with golden, crispy Vidalia onions that you can make in the air fryer or by frying in oil. (Directions for both methods are included below) It’s the perfect side dish for Thanksgiving or any holiday table. Once you try it from scratch, you’ll never go back to the canned version!

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Ok, I admit it- I LOVE the canned cream of mushroom soup and canned green bean version of green bean casserole. I just LOVE green bean casserole. I love it any way that it’s prepared. I’m not sure about you, but we had the canned green bean version at every single holiday when I was growing up, so there is a special place in my heart for it.

But, sometimes special occasions call for a homemade version. The from scratch version of green bean casserole is so different than the canned version; both are equally delicious, though. The scratch-made casserole has bright green beans, a creamy sauce made with a roux, whole milk and a little gruyere cheese, plus the onions are so crispy! I could eat the onions all by themselves.

I promise a homemade version is well worth the couple extra steps to prepare.

What You’ll Need

You can find the full, printable recipe with exact measurements at the bottom of this post. Read on for more details and tips!

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For the Crispy Onions (choose air fry OR fry in oil):
Air Fry Method:

• 2 Vidalia onions, thinly sliced
• 1 cup buttermilk
• 1 cup all-purpose flour
• 1 tsp salt
• ½ tsp black pepper
• 1 tsp paprika
• 1 tsp onion powder
• 1 tsp garlic powder
• Olive oil spray or avocado oil spray

Oil Fry Method:

• 2 large Vidalia onions, thinly sliced into rings
• 1 cup buttermilk (or milk)
• 1 cup all-purpose flour
• ½ cup cornstarch
• 1 tsp salt
• ½ tsp black pepper
• ½ tsp garlic powder (optional)
• ½ tsp paprika (optional)
• 3–4 cups vegetable oil, for frying

For the Casserole:

• 1 ½ lbs fresh green beans, cleaned and trimmed
• 1 tablespoon salt
• 3 tbsp butter
• 8 ounces mushrooms, sliced (button, baby bella, or cremini)
• 1 garlic clove, grated
• 2 tbsp all-purpose flour
• ½ tsp salt
• ½ tsp black pepper
• 1 tsp mustard powder
• 2 ½ cups whole milk or heavy cream
• ½ cup shredded Gruyère cheese
• 1/3 cup grated Parmesan cheese

How to Make Green Bean Casserole from Scratch

Step 1: Make the Crispy Onions

Air Fry Method:

1. Soak onions in buttermilk for at least 15 minutes.

2. Mix flour, salt, pepper, paprika, garlic powder, and onion powder in a shallow dish.

3. Drain onions, dredge in flour mixture, and shake off excess.

4. Preheat air fryer to 400°F. Spray basket with oil, add onions in a single layer, and spray the tops.

5. Air fry 7–10 minutes, shaking halfway, until golden. Transfer to a wire rack to cool and stay crispy.

Oil Fry Method:

1. Soak onions in buttermilk 20–30 minutes.
2. Whisk flour, cornstarch, salt, pepper, garlic powder, and paprika in a dish.
3. Heat oil in a skillet or Dutch oven to 350°F.
4. Dredge onions in flour mixture, then fry in batches for 2–3 minutes until golden.
5. Drain on paper towels and season lightly with salt.

Step 2: Blanch the Green Beans

1. Preheat oven to 350°F.
2. Bring a large pot of salted water to a boil.
3. Cook beans for 4 minutes, then transfer immediately to an ice bath to stop cooking. Drain and set aside.

Step 3: Make the Mushroom Cream Sauce

1. Melt butter in a large pan over medium heat.
2. Add mushrooms and cook 5–6 minutes until softened and liquid has evaporated.

3. Stir in garlic and cook 30 seconds.

4. Sprinkle flour, mustard powder, salt, and pepper over mushrooms. Whisk and cook for 1 minute.

5. Slowly whisk in milk or cream. Bring to a boil, stirring often, until thickened (about 5 minutes).

6. Remove from heat and stir in Gruyère and Parmesan until melted.

Step 4: Assemble the Casserole

1. Stir green beans and half the crispy onions into the mushroom sauce.

2. Spray a 9×13 baking dish with nonstick spray and pour in the mixture.

3. Cover with foil and bake 30 minutes, until bubbly.

4. Uncover, top with remaining onions, and bake 5 more minutes.

Serve warm and watch it disappear!

Did you enjoy this recipe? Take a picture and tag me @StephGigliotti on social media and #StephRealLife. I would absolutely love to see your finished dish!

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FAQ: Green Bean Casserole from Scratch

Can I make the onions ahead of time?
Yes! Fry or air fry the onions up to 1 day in advance. Store uncovered at room temperature. Re-crisp in a 375°F oven for 5–7 minutes before topping.

Can I prep the casserole ahead of time?
You can assemble the casserole (without the onions) up to 1 day ahead. Cover and refrigerate. Bake covered for 40 minutes, then add onions and bake 5 minutes more.

Can I freeze green bean casserole?
Yes, but freeze before baking for best texture. Thaw overnight in the fridge, then bake as directed. Add crispy onions after baking so they don’t soften.

Can I use canned green beans instead of fresh?
Fresh beans give the best texture, but you can substitute canned or frozen (thawed) green beans. If using canned, skip the blanching step.

What’s the best cheese for green bean casserole?
Gruyère adds a rich, nutty flavor, but Swiss or sharp white cheddar work great too.

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This scratch-made green bean casserole is comforting, creamy, and loaded with flavor—without a single can of soup. Whether you air fry the onions or fry them in oil, the homemade crispy topping makes this dish extra special. Perfect for Thanksgiving, Christmas, or any holiday meal!

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