Asparagus Casserole

Name: Asparagus Casserole
Prep time: 20 min
Cook time: 30 min
Total time: 50 min
Cuisine: Southern
Ingredients: 4 tablespoons (1/2 stick) butter; 2 1/2 pounds asparagus, (trimmed and cut into 1-inch pieces); 1 (8-ounce) package white mushrooms, (sliced); 1/2 medium sweet onion, (chopped); 1/4 cup all-purpose flour; 1 1/4 cup milk; 1/2 cup mayonnaise; 1/2 cup sour cream; 1/2 cup shredded cheddar cheese; 1/2 cup shredded swiss cheese; 1/2 teaspoon salt; 1/2 teaspoon lemon pepper; 1/4 teaspoon paprika; 1 (6-ounce) can french-fried onions