When the dough has proofed and has doubled in size, remove the plastic wrap and towel and punch dough down. Then, split dough in 2. Wrap one part with plastic to keep moist and spread the other one out using a rolling pin.
Use a bowl to cut circles into dough.
Spoon 2 or so tablespoons of filling into each circle.
Seal the buns by brushing with egg wash flipping the sides over the filling and pinching them together. Then lay buns down, with sealed side on the bottom on a parchment lined baking tray. Repeat until all the dough and filling are used up.
Preheat oven to 175 degrees, place a damp towel over the stuffed buns and place them in the oven to proof for another 30 minutes.
When they are done, they should be slightly bigger. Remove them from the oven and preheat oven to 375 degrees.
Beat the remaining egg and brush it over the buns.
Sprinkle buns with sesame seeds and place in 375 degree oven for 20-22 minutes.
Enjoy warm or at room temperature.