Mac & Cheese Canapes

I made these for the family Christmas party. Easy, and very yum! I reheated them at Annette's and they got a little dried out, so if you're in a similar situation, you might want to cover them with foil to keep some moisture in.
-Kathi
From: http://leitesculinaria.com/83177/recipes-mac-cheese-canapes.html

Mac and Cheese Canapés

Ingredients

• 1 tablespoon unsalted butter, plus more for the pans
• 1/4 cup toasted breadcrumbs (optional)
• 1/4 pound ditalini, which are essentially mini macaroni shapes, or other small, similarly shaped pasta
• 1 tablespoon all-purpose flour
• 1/3 cup whole milk, warmed
• 2 ounces sharp Cheddar, grated
• 2 ounces Gruyère, grated
• 1 large egg yolk
• 1 tablespoon heavy cream
• 1 teaspoon Dijon mustard (optional)
• Salt and freshly ground black pepper to taste

Directions

• 1. Preheat the oven to 425ºF (218ºC). Generously butter 24 mini muffin cups and, if desired, sprinkle with breadcrumbs. (If you’re baking the canapés in batches, reserve some of the butter and breadcrumbs, if desired, for the second batch.)
• 2. Bring a pot of salted water to a boil. Cook the pasta until it’s just barely beginning to soften and is at the early stages of al dente. Drain the pasta, rinse it under cold water, and return it to the pot.
• 3. Meanwhile, melt the 1 tablespoon butter in a small saucepan over medium-low heat. Stir in the flour and cook, still stirring constantly, for 1 minute, or until the mixture turns slightly beige and is bubbly. Increase the heat to medium and slowly whisk in the warm milk. Bring to a boil, whisking almost constantly. Reduce the heat to low and simmer for 2 minutes. Add the cheeses to the sauce in 1/2-cup increments, stirring until the cheese melts before making another addition. Pour the sauce over the pasta and stir well.
• 4. Beat the egg yolk with the cream and mustard, if using, and stir it into the pasta. Season with salt and pepper, and press the mixture into the prepared cups. (You may not fill all 24 of the cups.)
• 5. Bake the mini canapés for 10 to 12 minutes, or until the cheese sauce is bubbly and the tops are light brown. Let them rest for 5 minutes in the pan, then turn them out onto a platter and pass ASAP. The canapés can be baked, cooled, and refrigerated, tightly covered, for up to 2 days. Reheat them in a 375ºF (190ºC) until warmed through, 7 to 10 minutes.