Really Gouda Mac and Cheese

Ingredients (12)

• + 1 tablespoon salted butter add to pantry
• + 2 (3/4 inch thick) slices sourdough bread, or more to taste add to pantry
• + 1 serving cooking spray add to pantry
• + 1 (16 ounce) package elbow macaroni add to pantry
• + 4 cups freshly grated sharp Cheddar cheese add to pantry
• + 2 cups freshly grated smoked Gouda cheese add to pantry
• + 1 ½ cups whole milk, divided add to pantry
• ✓ 2 ½ tablespoons cornstarch
• + 2 ½ cups half-and-half add to pantry
• + 1 teaspoon pink Himalayan salt add to pantry
• + ½ teaspoon ground white pepper add to pantry
• + ½ teaspoon paprika add to pantry