Mini Macaroni and Cheese Appetizers

Bahan-bahan (48 porsi)

• 8 ounces small elbow macaroni
• 1½ tablespoons unsalted butter, (plus more for brushing)
• ¼ cup freshly grated Parmesan cheese
• 2 tablespoons all purpose flour
• ¾ cup milk
• 4 ounces (1 packed cup) shredded cheddar cheese
• 4 ounces deli sliced American cheese, (chopped)
• 1 large egg yolk
• ¼ teaspoon smoked Spanish paprika