1 package purchased puff pastry dough, defrosted
1 Tbsp olive oil
1 Tbsp minced onion
1 clove garlic, minced
2 Tbsp minced piquillo pepper
1/4 lb cremini or button mushrooms, brushed clean, finely chopped
1/2 medium-hot dried red chile pepper, such as guajillo (in the photo above), seeded and crumbled
Kosher or sea salt
Freshly ground black pepper
2 tsp grated cheese, such as manchego or Parmigiano-Reggiano
Heat the oil in a skillet and sauté the onion and garlic until the onion is wilted. Add the piquillo pepper and cook for a minute, then add the mushrooms, chile pepper, salt and pepper, and sauté until the mushrooms are softened. Remove from the heat and stir in the cheese.
Roll the puff pastry to 1/8 inch thick. Cut into 1-3/4- inch circles (you should get approximately 36 circles out of the dough), and place 1 tsp of filling on half of the circles. Moisten the edges with water (use your fingertip or a small pastry brush), cover with the remaining pastry circles, and press the edges with the tines of a fork to seal. [May be prepared ahead up to this point, and refrigerated. If you do this, let the pastries warm up at room temperature for 15 minutes before baking.]
Preheat oven to 425°F. Place the pastries on a rimmed baking sheet lined with a silicone mat (Silpat) or parchment paper. Bake on the upper rack of the oven for 7-10 minutes, or until golden.