Broccoli Rice Casserole

Name: Broccoli Rice Casserole
Ingredients: 4 tbsp. (1/2 stick) salted butter; 1 medium yellow onion, finely diced; 1 garlic clove, grated; 4 tbsp. all-purpose flour; 1/2 tsp. dry mustard; 1/4 tsp. cayenne pepper; 3 c. whole milk; 4 oz. cream cheese, at room temperature; 1/2 c. grated parmesan cheese; 1 tsp. black pepper; 1/2 tsp. kosher salt; 1/2 tsp. paprika; 8 oz. processed cheese (Velveeta), cubed; 3 c. grated sharp cheddar cheese (about 12 ounces); 8 c. small broccoli florets; 6 oz. diced pimentos, drained; 2 1/2 c. cooked long-grain rice