For the dish

• Preheat oven to 400°F. Line baking sheet with parchment paper.
• Place thawed puff pastry sheet on a surface very lightly dusted with flour. Using a rolling pin, gently roll out dough into a 9x12-inch rectangle. Using a pizza cutter, cut into 12 equal squares.
• In a small bowl, beat egg with water.
• Place half of a hot dog diagonally on each of the 12 squares of dough and fold opposite corners around the hot dog. Brush a small amount of egg wash along the seams to secure them.
• Brush the tops and sides of all pastries with the egg wash. Sprinkle tops with sesame seeds, poppy seeds or coarse salt, if desired.
• Bake in preheated oven for 25-28 minutes, until pastry is golden brown.
• Serve warm with ketchup and mustard for dipping.