In a skillet, sauté the chopped onion for 2 minutes. Add the garlic and sauté until the aromas are released.
Add the red pepper and cook for a few minutes. Reserve.
Breaking up the sausage with your hands, removing the film that wraps it.
Transfer to the previous skillet, cook until lightly browned. Add the onion, garlic and bell pepper.
Open the puff pastry sheet. Cut strips, from the center out, on both sides of the dough and leave a space in the center for the filling. Arrange the filling in the center and place the grated mozzarella over it . Braid the strips over the filling.
Brush with egg yolk and bring to a preheated oven at 356 degrees until golden brown.