How To Make Broccoli Casserole - Best Recipe | Charleston Magazine

Ingredients

• 8 cups water
• 3 Tbs., plus 1 tsp. kosher salt
• 2 broccoli crowns, cut into 2-inch florets
• 4 Tbs. unsalted butter
• 1/4 cup all-purpose flour
• 1 cup finely chopped onion
• 2 cups whole milk, room temperature
• 1 tsp. dry mustard
• 1 pinch cayenne pepper
• 1 pinch freshly grated nutmeg
• 1 cup freshly grated aged cheddar cheese
• 1/2 cup mascarpone cheese
• 1/2 cup freshly grated Parmesan cheese
• 1/2 cup dry bread crumbs