Gluten-Free Baked Macaroni and Cheese | America's Test Kitchen

Ingredients

• 3 slices (about 3 ounces) gluten-free sandwich bread , torn into quarters
• 2 tablespoons unsalted butter , melted, plus 4 tablespoons unsalted butter
• 12 ounces gluten-free caserecce or elbow macaroni
• Salt and pepper
• 2 1/2 cups whole milk
• 2 tablespoons cornstarch
• 1 garlic clove , minced
• 1/2 teaspoon dry mustard
• 1/8 cayenne pepper
• 1 cup chicken broth
• 12 ounces Colby cheese , shredded (3 cups)
• 6 ounces sharp cheddar cheese , shredded (1½ cups)