Preheat oven to 350 degrees F. Start boiling a large pot of water for pasta and cook pasta according to package directions. Meanwhile, brown sausage and mushrooms in a large skillet. Add garlic and cook for another 3-4 minutes, careful not to burn the garlic. Add the pasta sauce, herb blend and pepper flakes and simmer for 5 minutes.
Drain the cooked pasta and combine with the sausage mixture. Pour the pasta into a casserole dish and sprinkle the cheese on top.
Bake in the oven for 20-25 minutes. The pasta should be warmed through and the cheese should be melted.