Cheesy Mushroom and Onion Green Bean Casserole Recipe

This Cheesy Mushroom and Onion Green Bean Casserole takes the classic holiday side dish to spectacular new heights! With sautéed fresh mushrooms, caramelized sweet onions, and a kick of pepper jack cheese, this isn’t your grandmother’s green bean casserole. It’s creamy, crunchy, and utterly irresistible—perfect for both special occasions and weeknight dinners when you need some comfort food magic on your table in just 40 minutes.

Why You’ll Love This Recipe

• Elevated Classic: This isn’t just any green bean casserole—the addition of sautéed fresh mushrooms, sweet onions, and pepper jack cheese transforms it into something truly special without complicating the process.
• Make-Ahead Friendly: Prepare everything up to the final baking step and refrigerate until you’re ready to finish it off—perfect for busy holidays or hectic weeknights.
• Crowd Pleaser: The combination of creamy, cheesy goodness with the satisfying crunch of those crispy fried onions makes this dish impossible to resist. Even vegetable skeptics will be coming back for seconds!
• Versatile: Works beautifully as a holiday side dish but is simple enough for everyday dinners. It pairs with practically everything from roast turkey to weeknight chicken.

this Recipe

Ingredients You’ll Need

• Campbell’s Condensed Cream of Mushroom Soup: The foundation of our casserole, providing rich mushroom flavor and creamy texture. It’s a time-saver that doesn’t sacrifice taste.
• Milk: Creates the perfect consistency for our sauce. Use whole milk for maximum creaminess or lower-fat versions if preferred.
• Green Beans: The star vegetable! Canned green beans make this recipe super convenient, but you could substitute fresh (blanched) or frozen (thawed) if you prefer.
• French’s Crispy Fried Onions: These provide that signature crunch that makes this casserole so addictive. They’re non-negotiable for authentic flavor.
• Fresh Sweet Onion: Sautéing a fresh onion adds depth of flavor that takes this casserole to the next level. The caramelization brings out natural sweetness.
• Fresh Mushrooms: These add wonderful texture and amplify the mushroom flavor. White button or cremini mushrooms work perfectly.
• Butter and Olive Oil: The combination gives perfect flavor for sautéing our vegetables without burning.
• Pepper Jack Cheese: This is the game-changer ingredient! It adds a subtle heat and incredible meltiness that makes this casserole unforgettable.
• Seasonings: Simple salt and pepper enhance all the flavors without overwhelming the dish.

Variations

Make It Meatier

Add 1 pound of cooked, crumbled bacon or browned Italian sausage for a heartier casserole that could serve as a main dish.

Extra Veggies

Incorporate 1 cup of diced red bell peppers or water chestnuts for additional color, nutrition, and crunch.

Change the Cheese

Swap the pepper jack for smoked gouda, sharp cheddar, or gruyere for different flavor profiles. Each brings its own unique character to the dish.

Spice It Up

Add a dash of cayenne pepper, a tablespoon of hot sauce, or diced jalapeños if you want more heat than the pepper jack provides.

How to Make Cheesy Mushroom and Onion Green Bean Casserole

Step 1: Create Your Base

In a large mixing bowl, combine the Campbell’s Cream of Mushroom Soup with milk, salt, and black pepper. Whisk until smooth and well-blended.

Step 2: Sauté the Fresh Vegetables

Heat butter and olive oil in a sauté pan over medium heat. Add the diced sweet onion and mushrooms, cooking until they’re golden brown and tender—about 5-7 minutes. The caramelization here is critical for developing deep flavor.

Step 3: Combine Everything

Add your drained green beans to the soup mixture, then fold in the sautéed mushrooms and onions. Stir in 1 cup of pepper jack cheese until well incorporated. The mixture should be creamy and well-coated.

Step 4: First Bake

Transfer the mixture to a 3-quart casserole dish and bake uncovered at 350°F for 25 minutes. The casserole should be hot and bubbling around the edges.

Step 5: Add the Crispy Topping

Remove from oven and give the mixture a gentle stir. Top with the crispy fried onions and remaining 1/4 cup of cheese in an even layer.

Step 6: Final Bake

Return to the oven for just 5 minutes, or until the onions turn golden brown and the cheese is melted and bubbly. Watch carefully—those onions can burn quickly!

Pro Tips for Making the Recipe

• Don’t Skip the Fresh Sauté: Taking the time to properly sauté the fresh mushrooms and onion until golden makes all the difference in flavor depth.
• Drain Those Beans Well: Excess liquid from the canned green beans can make your casserole watery, so drain them thoroughly.
• Keep an Eye on That Final Bake: Those crispy onions can go from perfectly golden to burnt in a matter of minutes, so don’t walk away during that final baking step.
• Let It Rest: Allow the casserole to sit for 5 minutes after baking. This helps the sauce set up slightly and makes serving easier.
• Use a Clear Dish: If possible, bake in a clear glass dish so you can see when the sides are actively bubbling, which signals it’s hot throughout.

How to Serve

This casserole is incredibly versatile in how you can serve it:

Holiday Pairing

Serve alongside roast turkey, ham, or prime rib for a traditional holiday feast. The creamy, cheesy goodness perfectly complements roasted meats.

Weeknight Dinner Side

Pair with rotisserie chicken or grilled steak for an elevated yet easy weeknight dinner. The pepper jack gives just enough kick to wake up standard fare.

Potluck Star

This dish travels well and stays delicious even after sitting for a while, making it perfect for potlucks and family gatherings.

Make It a Meal

For a vegetarian main dish, serve larger portions alongside crusty bread and a simple green salad.

Make Ahead and Storage

Make Ahead

Prepare the casserole up to the first baking step. Cover and refrigerate for up to 24 hours. When ready to bake, add about 10 extra minutes to the initial baking time, then proceed with adding the toppings and final bake.

Storing Leftovers

Refrigerate leftovers in an airtight container for up to 3 days. The crispy onions will soften over time, but the flavor remains delicious.

Freezing

This casserole freezes beautifully before the final topping is added. Prepare through the first baking step, cool completely, then freeze for up to 3 months. Thaw overnight in the refrigerator before topping with the crispy onions and cheese for the final bake.

Reheating

Reheat individual portions in the microwave for 1-2 minutes. For larger amounts, cover with foil and reheat in a 325°F oven until hot throughout (about 20 minutes). You can add fresh crispy onions on top if you’d like to restore some crunch.

FAQs

Can I use fresh green beans instead of canned?
Absolutely! You’ll need about 1.5 pounds of fresh green beans, trimmed and cut into 2-inch pieces. Blanch them in boiling water for 3-4 minutes, then shock in ice water before adding to the casserole. This ensures they’ll be perfectly tender after baking.

My family doesn’t like spicy food. Can I still make this casserole?
Definitely! Simply substitute the pepper jack cheese with monterey jack, mozzarella, or mild cheddar cheese. You’ll still get the wonderful creaminess without the heat, and the casserole will be just as delicious.

Can this recipe be made gluten-free?
Yes, with a few adjustments. Use gluten-free cream of mushroom soup (or make your own with gluten-free flour), and check that your fried onions are gluten-free. There are several brands now making gluten-free fried onions, or you can make your own by coating thinly sliced onions in gluten-free flour and frying them until crisp.

How can I make this casserole a bit healthier?
Try using low-sodium cream of mushroom soup, 2% milk instead of whole, and increasing the ratio of fresh vegetables. You can also reduce the cheese by half and use a light sprinkle of the fried onions just on top rather than mixing them throughout.

Final Thoughts

This Cheesy Mushroom and Onion Green Bean Casserole brings warmth, comfort, and incredible flavor to any table. The combination of creamy, cheesy goodness with fresh sautéed vegetables and that irresistible crispy topping creates a dish that honors tradition while being exciting enough for contemporary tastes. Whether it’s gracing your holiday table or brightening a weeknight dinner, I’m confident this will become a requested favorite in your recipe collection. Give it a try—your taste buds (and dinner guests) will thank you!

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