Mini Cheeseburger Puff Pies
8 ounces ground beef
2 teaspoons ketchup
2 teaspoons Dijon mustard
1/4 teaspoon salt
1/4 teaspoon freshly ground black pepper
1 tablespoon extra virgin olive oil
All-purpose flour for dusting
1 sheet puff pastry (from a 17.5-ounce package)
2 ounces cheddar cheese, shredded (about 1/2 cup)
1 large egg beaten with 1 teaspoon water
Preheat oven to 400°F. Line a rimmed baking sheet with parchment paper; set aside.
In a large bowl, mix together the beef, ketchup, mustard, salt, and pepper. Form the mixture into 8 equal-size patties. In a large skillet, heat the oil over medium-high heat until shimmering. Brown the patties in oil about 1 minute per side.
On a lightly floured surface, unfold the pastry. Cut the pastry lengthwise into four equal strips, then cut strips in half crosswise. Place one patty on each strip and top with cheese. Fold the pastry up around the burgers and pinch the edges together to seal, molding to fit around the patties. Brush the tops of the pastries with the egg mixture.
Place the mini burgers on the prepared baking sheet. Bake for 12 to 15 minutes or until puffed and golden. Let stand for 5 minutes before serving.