Step 1

Preheat the oven to 425°. In a large saucepan of boiling salted water, cook the macaroni until al dente, about 5 minutes. Drain, shaking off the excess water.

Step 2

Brush four 12-cup, nonstick mini muffin tins with butter. Sprinkle with 2 tablespoons of the Parmigiano; tap out the excess.

Step 3

In a large saucepan, melt the 1 1/2 tablespoons of butter. Whisk in the flour over moderate heat for 2 minutes. Whisk in the milk and cook, whisking, until boiling, about 5 minutes. Add the cheddar and American cheeses and whisk until melted. Off the heat, whisk in the egg yolk and paprika. Fold in the macaroni.

Step 4

Spoon slightly rounded tablespoons of the macaroni into the prepared muffin cups, packing them gently. Sprinkle the remaining 2 tablespoons of Parmigiano on top.

Step 5

Bake the mini macs in the upper and middle thirds of the oven for about 10 minutes, until golden and sizzling. Let cool for 5 minutes. Using a small spoon, carefully loosen the mini macs, transfer to a platter and serve.