Preheat the oven to 425°F (218°C). Line 2 sheet pans with parchment paper. Then, whisk the egg with 1 Tablespoon (15 milliliters) of water in a small bowl. Set aside.

To make the honey mustard, combine the Dijon mustard and honey in a small bowl. Whisk until smooth.

Next, unroll one sheet of puff pastry on a lightly floured surface. Roll the puff pastry into a 9×12-inch rectangle. Using a sharp knife or pizza cutter, slice the puff pastry into 12 3×3-inch squares. Line the puff pastry squares on one of the prepared sheet pans about 2 inches apart. Place the sheet pan in the fridge to keep the puff pastry chilled. Repeat the process with the remaining sheet of puff pastry.

Use a the tines of a fork to lightly dock the centers of the puff pastry squares. Then, spoon a small dollop of honey mustard in the center of each puff pastry square. Top the honey mustard with a thin slice of cheese and a few pieces of ham.

Working one at a time, fold one corner of a puff pastry square over the ham and cheese. Then, brush the opposite puff pastry corner with a little egg wash. Fold the second puff pastry corner over the first, pressing firmly to seal. Use toothpicks to keep the puff pastry sealed, if needed. Fold the remaining bites.

Brush the outside of the puff pastry bites with the egg wash. Then, sprinkle the tops with sesame seeds, poppy seeds, or a mix of both.

Bake the bites for 20-23 minutes, until the puff pastry is golden-brown. Sprinkle the puffs with the minced chives. Enjoy warm!