Step 1

Preheat oven to 350°F and grease a 2-quart casserole dish with butter or nonstick spray. Set aside.

Step 2

Cook macaroni 1 to 2 minutes less than package directions call for, drain, and set aside.

Step 3

In a large skillet, season beef with garlic powder, thyme, salt, and pepper and brown with onions until cooked through and onions are tender.

Step 4

Stir in soup, milk, and mushrooms and season to taste.

Step 5

Arrange half of meat mixture into bottom of baking dish. Layer with half of the macaroni and half of the cheese. Layer once more with remaining meat and remaining macaroni.

Step 6

Bake uncovered for 20 minutes. Top with remaining cheese and bake until cheese is bubbly and golden brown, about 10 minutes more.