Southern Green Bean Casserole

Name: Southern Green Bean Casserole
Prep time: 15 min
Cook time: 30 min
Total time: 70 min
Ingredients: 1 large yellow onion, (thinly sliced); 2 tablespoons all-purpose flour; 1 tablespoon panko breadcrumbs; ¼ teaspoon kosher salt; ¼ teaspoon ground black pepper; neutral oil for frying; 1 tablespoon kosher salt; 1 pound fresh green beans, (trimmed and cut into 2-inch pieces); 1 ½ tablespoons unsalted butter; ½ pound mushrooms (cremini or button), (cleaned and sliced); ½ teaspoon kosher salt; ¼ teaspoon ground black pepper; 1 clove garlic, (minced); 1 ½ teaspoon all-purpose flour; ¾ cup heavy cream; ¾ cup chicken broth; ⅛ teaspoon ground nutmeg, (optional)

Growing up, green bean casserole never made an appearance at our holiday table. But when I married into my husband’s family, I quickly learned it wasn’t Thanksgiving without the traditional version (you know, the one made with cream of mushroom soup and topped with French’s crispy onions). While there’s nothing wrong with the classic (it’s a classic for a reason!), I love this version that keeps what everyone loves about the original, but uses fresh ingredients instead of canned.

baked green bean casserole in a 8x8 baking pan.

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I’m still not a fan of green beans, but this dish has completely won me over. It’s rich and creamy enough for Thanksgiving, but it’s easy enough for a weekly Sunday dinner. There’s something about the combination of fresh, tender green beans and that crispy topping that makes even a simple weeknight roast chicken feel special.

If you’re looking for more holiday sides that skip the shortcuts, you’ll love our Southern cornbread dressing, rosemary garlic mashed potatoes, and dry-brined spatchcock turkey.

Key Ingredients and Substitutions

Skip the canned soup—fresh ingredients make all the difference in this green bean casserole. Made completely from scratch, this recipe relies on fresh ingredients for the best flavor. You might already have most of these items in your kitchen.

In the printable recipe below, you can find a complete list of ingredients and measurements.

Fresh Green Beans: Fresh green beans give the best texture and flavor, but frozen green beans can work if needed. Skip the canned green beans – they’re too soft and won’t hold up during baking.
Mushrooms: Cremini mushrooms add a rich, earthy flavor, but white button mushrooms work well, too. Try a mix of wild mushrooms like shiitake, oyster, or maitake for added depth.
Heavy Cream: We used heavy cream to create the velvety base for our sauce. Half-and-half can work, but the sauce won’t be as thick. Milk makes the sauce too thin, so we don’t recommend it.
Panko Breadcrumbs: These Japanese-style breadcrumbs make extra crispy onions. Regular breadcrumbs work in a pinch, but panko gives the topping that light, crispy texture.
Yellow Onions: Pick large, firm onions for the crispiest results. Sweet onions can work, but have more water content, which might affect how crispy your topping gets.

How to Make Southern Green Bean Casserole

Here are the quick, step-by-step instructions with visuals; you can find the full instructions, including the exact ingredients, in the recipe card below.

Pro-tip: To ensure crispy onions, make them first and let them cool completely uncovered. This prevents steam from making them soggy while waiting for the casserole to bake.

1. Make the Crispy Onions: Line a baking sheet with several layers of paper towels and set aside. In a large bowl, toss your sliced onions with flour, panko, salt, and pepper until evenly coated. Heat 2 inches of oil in a large Dutch oven to 350°F. In batches, fry the onions for 1-2 minutes until light golden brown. Transfer to your prepared baking sheet using a slotted spoon, spreading them in a single layer.

onions in a bowl tossed with flour and panko.

2. Blanch the Green Beans: Bring a large pot of water to a boil and add 1 tablespoon salt. Add your green beans and cook for 5 minutes until bright green and crisp-tender. Immediately plunge them into an ice bath to stop the cooking process. Drain well and pat completely dry with paper towels.

green beans being blanched in hot water.

3. Make the Mushroom Sauce: Melt the butter in a large skillet over medium-high heat. Add the mushrooms, salt, and pepper, cooking until they release their moisture and the liquid evaporates, about 5-7 minutes. Add the garlic and cook until fragrant, about 1 minute. Sprinkle flour over the mushrooms and cook, stirring constantly, for 1 minute to remove the raw flour taste.

flour being stirred into the pan with the sautéing mushrooms.

4. Finish the Sauce: Slowly pour in the chicken broth while whisking constantly to prevent lumps. Once smooth, add the heavy cream and nutmeg. Simmer, stirring occasionally, until the sauce thickens enough to coat the back of a spoon, about 5-7 minutes.

chicken stock being whisked with the flour in the pan with the sautéing mushrooms.

cream added to the sautéed mushroom mixture.

5. Assemble and Bake: Heat your oven to 375°F. Fold the green beans into the mushroom sauce until well coated. Transfer to a buttered 8×8-inch baking dish. Bake for 20 minutes until bubbling around the edges. Top with your crispy onions and bake for 5 minutes more until the onions are deep golden brown. Serve alongside your other favorite Thanksgiving dishes.

green beans added to the mushroom mixture.

Make-Ahead and Storage

Make-Ahead: Each component of this green bean casserole can be prepared ahead of time. Make the crispy onions up to 3 days in advance and store them in an airtight container at room temperature. Blanch the green beans and prepare the mushroom sauce a day in advance, storing them separately in airtight containers in the refrigerator. The casserole can also be assembled (without the crispy onions), covered tightly with foil, and frozen in an airtight container for up to 3 months. When ready to bake, thaw in the refrigerator overnight, then bake as directed, adding about 10 minutes to the baking time. Add the crispy onions during the last 5 minutes of baking.

How to Store: Cool leftovers can be stored in an airtight container for up to 4 days in the refrigerator. To freeze, use a disposable aluminum pan or line your baking dish with heavy-duty foil before assembling. If using the foil-lining method, once frozen, remove the foil-wrapped casserole and store it in a freezer-safe container for up to 3 months. Remove any remaining crispy onions before freezing.

How to Reheat: Heat refrigerated portions in a 350°F oven until warmed through, about 15-20 minutes. For frozen casseroles in aluminum pans, bake straight from frozen at the original temperature (375°F) for about twice the original cooking time. Remove the foil cover during the last 15 minutes of baking. Add fresh crispy onions before serving.

Recipe Tips and Notes

Use a mandoline for perfectly sliced onions. It creates paper-thin, even slices that will fry up extra crispy. Just be sure to use the hand guard for safety since the blades are sharp!
Don’t skip blanching the green beans. Blanching helps the beans keep their bright green color and ensures they’re perfectly crisp-tender. Skipping this step can leave you with beans that are either too crunchy or too mushy.
Use fresh mushrooms, not canned. Fresh mushrooms create a richer sauce and better texture. Clean them with a damp paper towel instead of washing them – mushrooms that are too wet won’t brown properly.
Let the mushrooms cook properly. Don’t rush the process. They need time to release their moisture and brown, which develops a deep, rich flavor that makes the sauce special.
Keep those onions crispy. When frying, make sure your oil is at the right temperature (350°F). Too hot, and they’ll burn; too cool, and they’ll be greasy. Spread them out on paper towels while cooling, preventing steam from making them soggy.

Frequently Asked Questions

Three key steps prevent a soggy casserole: First, dry the blanched green beans before adding them to the sauce. Second, cook your mushrooms until all their moisture evaporates. Third, make sure your sauce is thickened correctly. It should coat the back of a spoon before combining it with the green beans.

Getting the right sauce consistency is crucial. Let your sauce simmer until it thickly coats the back of a spoon. If you can draw a line through the sauce on the back of the spoon and it holds, your sauce is ready. Also, make sure the blanched green beans are thoroughly dried to avoid adding any extra liquid.

More Thanksgiving Sides to Try

Looking for more classic Thanksgiving side dish recipes? Try these other favorites:

Southern Cornbread Dressing – Made with cornbread, celery, onions, and sage, this dressing is a Thanksgiving favorite and is also delicious with chicken or pork. This cornbread casserole is the classic comfort-food side dish.
Rosemary Garlic Mashed Potatoes – These mashed potatoes are made from cream infused with fresh rosemary and garlic. They are simple enough for weeknight dinners yet elegant enough to impress at holiday gatherings.
Orange Cranberry Sauce – Skip the can of jellied cranberry sauce. This homemade recipe is ready in 15 minutes. Flavored with orange juice and orange zest, it is a must on your Thanksgiving table.
Bourbon Sweet Potato Casserole – This easy make-ahead casserole recipe is a twist on a classic Thanksgiving side. It’s made with sweet potatoes, brown sugar, a couple of splashes of bourbon, and candied pecans.