Description
This Homemade Green Bean Casserole from scratch offers crispy fried onions, tender green beans, and a creamy mushroom sauce made without canned soup. Perfect as a comforting holiday side dish with fresh ingredients and rich flavors.
Ingredients
Scale
Fried Onions
- 1 yellow onion thinly sliced
- 1 red onion thinly sliced
- 2 1/2 cups buttermilk (see DIY below)
- 1 1/2 cups all-purpose flour
- 1 cup panko breadcrumbs
- 1/2 tsp salt
- 1/2 tsp pepper
- vegetable or canola oil for frying
Green Beans
- 1 3/4 pounds (28 oz) green beans trimmed and cut in half
- 3 tablespoons unsalted butter
- 2 tablespoons olive oil
- 12 oz cremini mushrooms sliced 1/4” thick
- 4 garlic cloves minced
- 1 teaspoon salt
- 1/3 cup all-purpose flour
- 3 cups low sodium chicken broth
- 1/2 cup heavy cream
- 1 1/2 teaspoons Dijon mustard
- 1 1/2 teaspoons Worcestershire sauce
- 1 teaspoon dried thyme
- 1 teaspoon dried parsley
- 1/2 teaspoon pepper
- 1/4 teaspoon dried oregano
- 1/4 teaspoon nutmeg
- 1/2 cup freshly grated cheddar cheese
- 1/4 cup freshly grated Parmesan cheese
- 1/2 cup sour cream
Instructions
- Soak Onions: Add sliced yellow and red onions to a shallow baking dish and pour buttermilk over top, pressing onions down to submerge as much as possible. Let soak at room temperature for 1 hour, stirring occasionally. Cover and refrigerate if soaking longer.
- Prepare Oil and Coating: Heat 2 inches of vegetable or canola oil in a deep heavy-duty pot or Dutch oven to 375 degrees F. In a large bowl, mix flour, panko breadcrumbs, salt, and pepper. Line a baking sheet with paper towels.
- Fry Onions: Test oil temperature with a pinch of panko; if it bubbles and fries, it’s ready. Using tongs, dredge onion slices from buttermilk into the flour mixture, shaking off excess, then carefully fry in hot oil until lightly golden brown, about 1-2 minutes. Stir gently while frying to separate onions. Remove with slotted spoon to paper towels. Repeat with remaining onions.
- Blanch Green Beans: Bring a large pot of water to a boil with 2 tablespoons salt. Add green beans and blanch for 5 minutes. Transfer to ice water to stop cooking; drain and pat dry.
- Cook Mushrooms and Garlic: Melt butter with olive oil in a Dutch oven or large pot over medium heat. Add mushrooms and cook until browned and softened, about 3-5 minutes. Season with salt and add minced garlic; sauté for 30 seconds.
- Make Sauce Base: Whisk in flour and cook while stirring for 1 minute to eliminate raw taste. Reduce heat to low and gradually whisk in chicken broth and heavy cream, then add Dijon mustard, Worcestershire sauce, dried thyme, parsley, pepper, oregano, and nutmeg.
- Simmer Sauce: Bring sauce to a boil whisking constantly, then reduce heat to simmer. Continue whisking often until thickened, about 5 minutes.
- Add Cheeses and Sour Cream: Remove from heat and whisk in cheddar cheese until melted, then Parmesan cheese. Finally, whisk in sour cream until smooth and blended.
- Combine Green Beans and Sauce: Add the dried green beans and 1 1/2 cups of fried onions to the sauce. Stir to combine thoroughly. Add a little broth if sauce is too thick.
- Bake Casserole: Transfer mixture to a lightly greased 9×13 inch baking dish. Top with remaining fried onions as desired. Bake in a preheated 350 degrees F oven for 15-20 minutes until hot and bubbly.
Notes
- DIY Buttermilk: Combine 2 1/2 tablespoons lemon juice or white vinegar with milk to equal 2 1/2 cups, stir, let curdle 10-15 minutes before using.
- Use pre-cut and pre-washed green beans to save prep time but still trim and halve them.
- Pat green beans very dry after blanching to prevent runny sauce.
- Cook mushrooms until browned and moisture released before adding salt to help browning.
- Cook flour for full 1-2 minutes until nutty smell develops to avoid raw flour taste.
- Keep heat low when adding broth and cream, stirring constantly to prevent lumps.
- Simmer sauce until it coats the back of a spoon but do not over-thicken as cheese and sour cream thicken further.
- If sauce thickens too much, thin gently with additional chicken broth.
- Slice onions thinly for ideal coating and texture; use a mandoline slicer for convenience.
- Fry onions at 375 degrees F to get crispy edges without burning; do a small test batch first.
- Onions fry quickly in 1-2 minutes; watch closely and remove when lightly golden, not dark.
- Fried onions can be made ahead and stored at room temperature up to 3 days.
- Green bean casserole can be assembled ahead (without onions), refrigerated, then baked with onions added near the end for best texture.
- Store leftovers in airtight container in refrigerator up to 5 days; onions may lose crispness on reheating.
