Green Bean Casserole Recipe (From Scratch with Crispy Fried Onions)

This Green Bean Casserole recipe takes the classic holiday side dish to the next level with fresh green beans, homemade creamy mushroom sauce, and crispy fried onions. Instead of relying on canned cream of mushroom soup, this version uses simple ingredients to create a rich, savory sauce from scratch.
The combination of tender green beans, sautéed mushrooms, garlic, and a creamy homemade sauce makes every bite satisfying. Topped with golden fried onions, it has the perfect contrast of creamy and crispy textures.
You can also save time with store-bought fried onions or prepare some of the components ahead, making this homemade green bean casserole easier to fit into a busy holiday cooking schedule.

Why You’ll Love This Green Bean Casserole

• Made from scratch: The creamy mushroom sauce is homemade, with no canned soup needed.
• Fresh ingredients: Fresh green beans, baby bella mushrooms, garlic, and yellow onion create plenty of savory flavor.
• Crispy topping: Homemade fried onions add a crunchy golden layer.
• Flexible preparation: Use store-bought fried onions when you need a shortcut.
• Make-ahead friendly: Prepare the green beans and fried onions ahead to save time on the day you serve it.

Ingredients You’ll Need

This recipe uses fresh vegetables, dairy, flour, and seasonings to create a creamy casserole with a crispy onion topping.

For the Green Bean Casserole

• Green beans: Fresh green beans are the base of the casserole. Blanching them before baking helps prepare them for the oven.
• Canola oil: Used to sauté the vegetables for the mushroom sauce.
• Yellow onion: Adds a savory, slightly sweet flavor to the sauce.
• Baby bella mushrooms: Give the homemade sauce its rich mushroom flavor.
• Garlic: Adds depth and aroma.
• All-purpose flour: Helps thicken the creamy mushroom sauce.
• Whole milk and heavy whipping cream: These create the smooth, rich consistency that coats the green beans.
• Salt and fresh cracked black pepper: Season the sauce and bring the flavors together.

For the Homemade Fried Onions

• Yellow onions: Thinly sliced onions become crisp and golden when fried.
• Low-fat buttermilk: Helps the flour coating cling to the onion slices.
• All-purpose flour: Creates the crispy outer coating.
• Coarse kosher salt, black pepper, and garlic powder: Season the fried onions.

Helpful Tips for the Best Results

• Slice the onions thinly: Thin slices help the fried onions become crispy and cook quickly.
• Blanch the green beans: Boiling them for 2–4 minutes before transferring them to ice water helps prepare them for baking.
• Dry the green beans: Pat them dry after cooling so excess water doesn’t get into the casserole.
• Fry in small batches: Avoid overcrowding the skillet so the onions can turn golden brown.
• Keep the fried onions uncovered: Let them cool in a single layer without covering them to help preserve their crispness.
• Whisk the sauce gradually: Slowly pour in the milk and cream while whisking to help create a smooth sauce.
• Choose your preferred texture: The casserole can bake for 35–45 minutes depending on whether you prefer crunchier or softer green beans.

How to Make Green Bean Casserole

Step 1: Make the Homemade Fried Onions

Thinly slice the two large yellow onions and place them in a bowl. Cover them with low-fat buttermilk and let them soak for 10–15 minutes.
Meanwhile, combine the flour, coarse kosher salt, black pepper, and garlic powder in a separate bowl.
Heat about 2 inches of oil in a heavy skillet to 350°F. Prepare a baking sheet with a couple of layers of paper towels.
Remove batches of onions from the buttermilk, shaking off the excess. Toss them in the seasoned flour mixture until coated.
Fry the onions in small batches for 1–2 minutes, until golden brown. Use a metal strainer to transfer them to the paper towels. Spread them out to cool without covering them.

Step 2: Blanch the Green Beans

Trim the ends of the green beans where they were attached to the vine. You can leave them whole or cut them in half.
Prepare a large bowl of ice water by combining cold water with a couple of cups of ice.
Bring a large pot of water to a boil and add the green beans. Boil for about 2–4 minutes, depending on their thickness.
Immediately transfer the green beans from the hot water into the ice water. Once cooled, remove them and pat them dry with paper towels.

Step 3: Prepare the Creamy Mushroom Sauce

Preheat a large cooking pan over medium heat. Thinly slice the small yellow onion and baby bella mushrooms.
Add the canola oil and sliced onion to the pan. Sauté until the onion becomes transparent.
Add the mushrooms and cook until mostly done. Mince or press the garlic cloves and stir them into the pan. Cook until fragrant.
Sprinkle the flour over the vegetables and stir until everything is coated.
Slowly pour in the milk while whisking continuously. Add the heavy whipping cream while continuing to stir. Keep stirring gently as the sauce thickens.
Season with salt and fresh cracked black pepper. Cook for a couple more minutes, then remove the pan from the heat.

Step 4: Assemble the Casserole

Preheat the oven to 375°F and lightly grease a 9×13 casserole dish.
Add the blanched green beans to the dish. Pour the creamy mushroom sauce over them and add ½ cup of the fried onions.
Mix everything together until the green beans are evenly coated with the sauce.

Step 5: Bake and Add the Crispy Topping

Cover the casserole dish with foil and bake for 35–45 minutes, depending on how crunchy or soft you want the green beans.
Remove the dish from the oven and carefully take off the foil. Spread the remaining fried onions evenly over the top.
Return the casserole to the oven and bake uncovered for another 7–10 minutes.
The casserole is ready to serve with its creamy mushroom sauce and golden crispy onion topping.

Easy Shortcut: Use Store-Bought Fried Onions

Making fried onions from scratch adds a homemade touch, but you can save preparation time by using store-bought fried onions.
For this shortcut, use one 6-ounce package of French’s Fried Onions instead of making the homemade topping. You can also look for gluten-free fried onions if you need a gluten-free option.
If you’re making the homemade fried onions gluten-free, use gluten-free all-purpose flour instead of regular flour.

Make-Ahead Tips

You can prepare a few components before assembling the casserole:

• Green beans: Blanch the green beans and store them in the refrigerator or freeze them until needed.
• Fried onions: Prepare the homemade fried onions and store them in a large airtight container in a cool, dry place for a day. Refrigerate them if you need to keep them longer.
• Crisp up the onions: If the fried onions lose some of their crispness, warm them in the oven at 375°F to crisp them back up.

Preparing these components ahead makes assembling the casserole easier when you’re getting ready for a holiday meal.

What to Serve with Green Bean Casserole

This homemade green bean casserole is a natural fit for holiday dinners and family meals. Serve it alongside roasted beef, turkey, chicken, or other main dishes.
It also works well with other classic side dishes, especially mashed potatoes and roasted vegetables. The creamy mushroom sauce and crispy onion topping make it a satisfying addition to a holiday spread.

Frequently Asked Questions

Can I use canned green beans instead of fresh?

This recipe is written for fresh green beans, which are blanched before being added to the casserole. The cooking instructions and timing are based on that preparation.

Can I use store-bought fried onions?

Yes. Use one 6-ounce package of French’s Fried Onions instead of making the homemade fried onions. This is a convenient shortcut when you’re short on time.

Can I make green bean casserole ahead of time?

Yes. You can blanch the green beans ahead and store them in the refrigerator or freezer. You can also prepare the fried onions in advance and crisp them back up in the oven at 375°F if needed.

How should I store leftover green bean casserole?

Transfer leftovers to an airtight food storage container and refrigerate for 3–4 days.

How do I reheat green bean casserole?

Reheat individual portions in the microwave in 30-second increments. You can also warm the casserole in the oven at 350°F until just hot.

How to Store and Reheat

Store leftover green bean casserole in an airtight food storage container in the refrigerator for 3–4 days.
For individual servings, reheat in the microwave in 30-second increments. To warm a larger portion, place it in the oven at 350°F until just hot.

A Homemade Holiday Side Dish Worth Making

This Green Bean Casserole combines fresh green beans, a creamy homemade mushroom sauce, and crispy fried onions for a flavorful take on a holiday classic. Make the fried onions from scratch for extra homemade flavor, or use the store-bought shortcut when you need to save time. Either way, it’s a comforting side dish that fits beautifully into a family dinner or holiday menu.

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