Southern Green Bean Casserole

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 with the exact ingredients in the recipe card below.
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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.

2. Blanch the Green Beans: Bring a large pot of water to 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.

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.

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.

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.

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 make the mushroom sauce a day before, 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—those 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