Green Bean Casserole (from scratch) 

Prep Time: 25 minutes | Cook Time: 50 minutes



  • Crunchy Onion Topping
  • 1 large onion, thinly sliced (Check out our handy how-to video)
  • 1/2 cup flour, all purpose
  • 3/4 cup Japanese bread crumbs
  • 1/2 tsp salt
  • 1/2 tsp pepper
  • 1 large egg
  • 1 tbs milk
  • Beans and Sauce
  • 1 lb green beans, trimmed and halved
  • 1 tbs kosher salt
  • 1 gal water
  • 2 tbs butter
  • 12 oz mushrooms, quartered or halved
  • 2 cloves garlic, minced
  • 1/4 tsp ground nutmeg
  • 2 tbs all-purpose flour
  • 3/4 cup chicken broth
  • 1 1/4 cup half-and-half


Crunchy Onion Topping

Preheat oven to 475 F. Prepare a baking sheet by lining with parchment paper.

Create an assembly line of bowls, beginning with flour in the first.

In a separate bowl, whisk together the egg and milk.

In a third bowl, combine breadcrumbs, salt, and pepper.

Working with a few at a time, dip the onion slices first in flour, next the egg mixture, then the breadcrumbs. Place onto baking sheet.

Bake until golden brown, about 25 minutes. Flip twice while cooking. Once done, remove from oven and reduce oven heat to 400 F.

Beans and Sauce

Bring 1 gallon of water and 2 tbs salt to a boil. Add the green beans and cook for 5 minutes, then drain and plunge in ice water. Drain again and set aside.

Melt 2 tbs butter over medium-high heat.

Add the mushrooms then salt and pepper to taste. Stirring occasionally, cook until the mushrooms begin to give up some of their liquid, about 4-5 minutes.

Add the garlic and nutmeg, then continue to cook another 1-2 minutes.

Sift or sprinkle in flour. Stirring constantly, cook for another minute.

Add broth and let simmer for 1 minute. Decrease the heat to medium-low and add the half-and-half. Stirring occasionally, cook until mixture thickens, about 8-10 minutes.

Remove from heat and add the green beans. Stir to coat and combine.

Transfer to oven-safe container, top with crunchy onions, and bake until bubbly, about 15-20 minutes.


To make ahead, keep the topping and beans separate until you're ready to bake and serve. Love the recipe but don't have the time? Try our 30-Minute Green Bean Casserole!