Description

This from-scratch green bean casserole features tender green beans, a velvety homemade mushroom cream sauce, and double the crispy onions for the ultimate crunch. It’s a showstopper dish that’s surprisingly easy to make and perfect for potlucks, holidays, or any gathering.

Ingredients

Scale

2 large yellow onions, thinly sliced into rings (about 4 cups)
1 cup buttermilk
1 ½ cups all-purpose flour
1 teaspoon garlic powder
1 teaspoon smoked paprika
1 teaspoon salt
½ teaspoon black pepper
Vegetable oil for frying (about 2-3 cups)
1 ½ pounds fresh green beans, trimmed and cut into 2-inch pieces
3 tablespoons unsalted butter
8 ounces cremini mushrooms, thinly sliced
1 medium yellow onion, finely diced
3 cloves garlic, minced
3 tablespoons all-purpose flour
1 ½ cups whole milk
1 cup heavy cream
1 teaspoon salt
½ teaspoon black pepper
¼ teaspoon nutmeg
½ cup grated Parmesan cheese
¼ cup panko breadcrumbs

Instructions

Prepare the crispy onions: Slice onions into thin rings, separate, and soak in buttermilk for at least 15 minutes. In a separate bowl, mix flour, garlic powder, smoked paprika, salt, and pepper. Heat 2 inches of vegetable oil in a skillet to 350°F. Working in batches, dredge soaked onion rings in seasoned flour, shaking off excess. Fry for 2-3 minutes per side until golden brown. Transfer to paper towels and season with salt. Set aside.
Blanch the green beans: Bring a large pot of salted water to a boil. Add green beans and cook for exactly 3 minutes. Drain and transfer to a bowl of ice water to stop cooking. Let sit for 2-3 minutes, then drain well and pat dry.
Make the creamy mushroom sauce: In a medium saucepan, melt butter over medium heat. Add sliced mushrooms and diced onion, cook for 6-8 minutes until mushrooms release liquid and start to brown. Add minced garlic and cook 30 seconds. Sprinkle flour over mixture and stir constantly for 1 minute. Slowly pour in milk and heavy cream, whisking continuously. Bring to a gentle simmer and cook for 3-4 minutes until thickened. Season with salt, pepper, and nutmeg. Remove from heat and stir in Parmesan un…
Assemble the casserole: Preheat oven to 375°F. In a large bowl, combine blanched green beans, mushroom sauce, and half of the crispy onions. Gently fold until evenly coated. Transfer to a greased 9×13 baking dish. Sprinkle panko breadcrumbs over the top, then add remaining crispy onions in an even layer.
Bake for 20-25 minutes until bubbly around edges and top is golden brown. Let rest for 5 minutes before serving.

Notes

For best results, don’t skip blanching the green beans—it ensures perfect crisp-tender texture. Keep oil temperature steady when frying onions; work in small batches. Season each component as you go for layered flavor. The mushroom sauce can be made up to 2 days ahead; crispy onions stay crunchy in an airtight container for up to 3 days. If top browns too quickly, tent with foil. For gluten-free, use 1:1 gluten-free flour blend and gluten-free panko. For dairy-free, use vegan butter, unsweetened oat milk or full-fat coconut milk, and plant-based Parmesan.

Prep Time: 20 minutes
Cook Time: 25 minutes
Category: Side Dish
Cuisine: American

Nutrition

Serving Size: 1 serving (about 1 c
Calories: 385
Sugar: 8
Sodium: 620
Fat: 22
Saturated Fat: 10
Carbohydrates: 38
Fiber: 4
Protein: 12

Keywords: green bean casserole, crispy onions, homemade, from scratch, Thanksgiving, potluck, side dish, vegetarian