Creamy Parmesan Green Bean Casserole Recipe

If you’re searching for the ultimate comfort-food side dish, Creamy Parmesan Green Bean Casserole is about to steal the show. Think: crisp-tender green beans bathed in a luxuriously cheesy sauce, peppered with earthy mushrooms, and all crowned with the irresistible crunch of golden fried onions. It’s everything you love about the classic, elevated with a Parmesan-packed twist.

Ingredients You’ll Need

You only need a handful of essential ingredients to create this showstopper—each one brings something special, from creamy texture and nutty flavor to savory crunch. With fresh green beans as the star and just a few pantry favorites, Creamy Parmesan Green Bean Casserole proves that simple can be downright spectacular.

• Fresh green beans (2 pounds): Washed and trimmed, these give your casserole an unbeatable crisp-tender bite and beautiful color—so much better than canned!
• Salted butter (1/2 cup): Adds richness and flavor to the mushroom base—use a good quality for the best results.
• Baby bella mushrooms (8 ounces, chopped): Their earthy depth pairs perfectly with the Parmesan and turns the sauce downright dreamy.
• All-purpose flour (2 tablespoons): Just enough to thicken the creamy sauce—don’t skip this step!
• Heavy cream, half & half, or whole milk (1 1/2 cups): Pick whichever you prefer for varying levels of richness—the creamier the better in my book.
• Salt (1 1/2 teaspoons) and pepper (1/2 teaspoon): Simple seasonings that bring all the flavors together, letting each ingredient shine.
• Parmesan cheese (2 cups, freshly grated): The magic ingredient! Freshly grated melts silkily into the sauce, delivering depth and salty-nutty flavor.
• French fried onions (2 cups): That iconic, golden topping—salty, crisp, and truly everyone’s favorite part.

Variations

One of the joys of Creamy Parmesan Green Bean Casserole is how customizable it is—feel free to tweak based on what’s in your fridge, your dietary preferences, or just for fun. Here are my favorite playful twists to make this classic your own:

• Make it gluten-free: Swap the all-purpose flour for your favorite gluten-free flour blend and double-check your fried onions for wheat-free options.
• Add a protein boost: Stir in cooked and crumbled bacon or diced rotisserie chicken before baking for a more filling main dish version.
• Try a different cheese: Not a Parmesan fan? Shredded Gruyère or extra-sharp cheddar bring a whole new layer of flavor to the sauce.
• Go dairy-free: Use plant-based butter, dairy-free milk or cream, and a vegan Parmesan substitute—delicious and just as creamy!

How to Make Creamy Parmesan Green Bean Casserole

Step 1: Prep the Green Beans

Preheat your oven to 375°F. Give your green beans a quick wash and trim the ends—this little bit of TLC ensures each bean cooks up snappy and vibrant. Arrange them in a single layer in your 9×13-inch baking dish so every bean gets plenty of sauce love.

Step 2: Sauté the Mushrooms

Grab your biggest skillet and melt the butter over medium-low heat. Add your chopped mushrooms along with the salt and pepper; sauté, stirring often, for about 4–5 minutes. The mushrooms should soften and deepen in flavor, making your kitchen smell absolutely heavenly at this point!

Step 3: Make the Creamy Sauce

Sprinkle in the flour and keep stirring for another minute or two—this forms a simple roux to thicken your sauce. Pour in your cream (or milk) and cook just until you see little bubbles forming around the edges. Now comes the magic moment: stir in all that freshly grated Parmesan. Continue stirring gently until the cheese fully melts and the sauce thickens to creamy perfection, just a couple minutes more.

Step 4: Assemble the Casserole

Pour your luscious Parmesan-mushroom sauce evenly over the green beans. Give everything a gentle stir so the beans are well coated from tip to tail. Top generously with the French fried onions—don’t skimp! They’re the crowning glory of a true Creamy Parmesan Green Bean Casserole.

Step 5: Bake to Golden Perfection

Bake your casserole uncovered for 45 minutes. Check for doneness: if the beans are still a little too crisp for your taste, cover loosely with foil and bake for another 10–15 minutes. The result should be bubbling edges, a golden cheesy crust, and fried onions so crisp you can hear them crunch from the next room.

How to Serve Creamy Parmesan Green Bean Casserole

Garnishes

Give your Creamy Parmesan Green Bean Casserole an extra burst of color and flavor with a sprinkle of fresh chopped parsley or chives just before serving. A touch of lemon zest or a dusting of extra Parmesan never hurts, either—both add brightness that lifts those rich, creamy flavors right off the plate!

Side Dishes

This casserole is holiday-table royalty, but don’t restrict it to just Thanksgiving! It plays beautifully with roast chicken, glazed ham, herb-crusted pork, or even as a companion to simple weeknight grilled steaks. Add classic mashed potatoes or honey-glazed carrots for a cozy, crowd-pleasing meal.

Creative Ways to Present

For a dinner party or potluck, scoop individual portions into ramekins and give each a final fried onion flourish right before serving. Or try assembling mini casseroles in ovenproof mugs for a playful personal touch—guests will adore their own bubbling, golden-topped Creamy Parmesan Green Bean Casserole.

Make Ahead and Storage

Storing Leftovers

Leftover Creamy Parmesan Green Bean Casserole keeps beautifully in the refrigerator for up to five days. Just transfer any extras to an airtight container or cover the casserole dish tightly with foil to lock in freshness and prevent the topping from going stale.

Freezing

If you want to get ahead on holiday prep, freeze the assembled casserole (without the fried onions) for up to two months. Thaw overnight in the fridge, add the crunchy topping just before baking, and cook as usual. This keeps the onions crisp and your casserole tasting freshly made.

Reheating

To reheat, cover with foil and warm in a 350°F oven for about 15–20 minutes, or until heated through. If you like an ultra-crispy topping, remove the foil for the last 5 minutes and maybe add a fresh sprinkle of fried onions to restore that irresistible crunch.

FAQs

Final Thoughts

I can’t recommend this Creamy Parmesan Green Bean Casserole enough—every time I make it, someone inevitably asks for the recipe. Whether you’re sharing it at a big holiday dinner or just cozying up for a weeknight treat, this is one of those lovingly homemade sides that turns an ordinary meal into something truly memorable. Give it a try and let the compliments roll in!

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