Mushroom and Green Bean Casserole

  • Post category:Recipes

Mushrooms are an under-appreciated food. Maybe because they aren’t a rainbow color! However, brown and white is beautiful too. Mushrooms are a powerhouse of healthy phytonutrients and are prebiotics that feed healthy gut bacteria. In this healthy holiday version of green bean casserole, mushrooms take center stage combining with the nutritional value of green beans, onions, garlic, and thyme.

For more health information about mushrooms, click here. 

Mushroom and Green Bean Casserole

Makes 8 servings


1 cup Frenches fried onions or homemade*

2 pounds fresh green beans, trimmed and halved

1 pound cremini mushrooms, sliced

2 Tablespoons extra virgin olive oil, divided

4 large sprigs thyme

6 Tablespoons salted European butter (Kerrygold)

1 shallot finely diced

3 cloves of garlic, minced

3 Tablespoons all purpose flour

1 1/2 cups chicken stock

1/4 cup heavy cream

1/2 cup Parmesan cheese

Kosher salt and pepper


  1. Preheat oven to 375 degrees F. Prepare the green beans and blanch in a large pot of salted boiling water until bright green and tender (7 to 10 minutes). Drain in a colander and set aside.
  2. In a large skillet with 1 Tablespoon olive oil cook half of the mushrooms without stirring until golden brown underneath. Toss and cook until both sides are brown. Add 2 Tablespoons of butter and 2 thyme sprigs. Cook until butter browns and mushrooms are very brown and tender. Remove thyme and transfer to a plate. Repeat with the other half of the mushrooms.
  3. In the same skillet, melt the remaining 2 Tablespoons of butter over medium low heat. Add the diced shallot and minced garlic. Cook until tender and then whisk in the flour. Increase heat and cook until the roux is golden brown, about 4 minutes. Whisk in chicken stock and cream. Bring to a simmer, whisking often and cook until thick and bubbling. Remove from heat and whisk in Parmesan cheese.
  4. Combine green beans, mushrooms and sauce and pour into a 4-quart baking dish. Cover tightly with foil and bake until sauce is bubbling, 25 to 30 minutes. Uncover and continue to bake until lightly browned on top and around the edges, about 20 minutes. Top with onions and bake about 5 minutes more.

*Homemade fried onions:


1 onion

1/2 quart buttermilk

2 1/2 cups flour

salt and pepper

peanut oil


  1. Soak sliced onions in buttermilk for 20 minutes. Mix flour and seasoning in a bowl for dipping the onions.
  2. Heat 2 to 3 inches of oil in a large pot to 350 degrees F. Drain a few onion slices at a time and coat in the flour mixture shaking off excess. Fry until golden browned, 4 to 6 minutes. Drain on a plate lined with paper towels.


 Adapted from