Preheat your oven to 400°F (200°C). Roll out the thawed puff pastry sheets slightly on a surface, cut into squares or rectangles, and chill on a parchment-lined baking sheet.

In a medium skillet, melt about a tablespoon of butter over medium heat. Whisk three large eggs with a splash of milk or cream, then pour into the skillet and stir until creamy, about 3-4 minutes.

Add a generous spoonful of scrambled eggs to the center of each pastry square. If desired, add a whole runny yolk on top and sprinkle cheese over the filling.

Cover each filled pastry with another square or fold into a triangle. Crimp the edges with a fork to seal. Brush tops with beaten egg and add sesame seeds if desired.

Bake for 15-18 minutes until puffed and golden brown. Allow to cool slightly on a wire rack before serving.