Green Bean & Mushroom Mac Casserole

Green Bean & Mushroom Mac Casserole


  • 4 tablespoons butter, cut into pieces
  • 1/2 pound cremini mushrooms, sliced
  • 2 large shallots, chopped
  • 4 cloves garlic, chopped
  • 2 tablespoons fresh thyme leaves, chopped
  • Salt
  • 3 tablespoons flour
  • 1/2 cup dry sherry or white wine
  • 1 pint (2 cups) half-and-half
  • 1 cup chicken stock
  • White pepper, to taste
  • 2 cups shredded white sharp cheddar
  • 1/2 cup grated Parmigiano-Reggiano
  • 1 pound short-cut pasta, such as cavatappi (hollow corkscrew pasta), penne or shells
  • 1 package (12 oz.) trimmed haricots verts or green beans, halved crosswise
  • 1 container (2.8 oz.) fried onions (I like French's)


In a large skillet, melt the butter over medium to medium-high. Add the mushrooms and cook, stirring occasionally, until browned, 3 to 5 minutes. Add the shallots, garlic and thyme; season with salt. Cook, stirring occasionally, until the shallots soften, 2 to 3 minutes more. Sprinkle with the flour; stir 1 minute. Stir in the sherry, then the half-and-half and stock. Bring to a bubble and cook, stirring occasionally, until the sauce thickens, about 3 minutes. Season with white pepper. Add both cheeses; stir until melted, about 2 minutes.

Meanwhile, bring a large pot of water to a boil for the pasta. Salt the water, add the pasta, and cook 5 minutes. Add the green beans and cook until the pasta is al dente, 2 to 3 minutes more. Drain the pasta and green beans; mix into the mushroom cheese sauce. Transfer to a casserole dish and top with the fried onions.