Preheat oven to 400F. Line baking sheet with aluminum foil.
Mince the bacon and jalapeños, ribs and seeds included for extra spice.
On a lightly floured surface roll out the puff pastry to 1/8-inch thick. Cut into 2-inch squares.
Working with one square at a time, add 1/2 tablespoon of filling to the center. Brush the edges with water, then fold over and press edges together to seal.
Transfer to the prepared baking sheet and repeat with remaining puff pastry squares and filling. Brush the bites with melted butter then transfer to oven. Bake until golden and fluffy, 15 minutes. Serve warm.