Lay the thawed puff dough out on a cutting board. Cut into 8 equal squares. Break the chocolate bar into 8 pieces. Place a piece of chocolate in the center of each square. Place 1 tablespoon of jam on top of each chocolate piece. Turn the corner of each square of puff dough onto the opposite corner and press the edges together to seal. Place on a parchment-lined baking sheet. Brush each turnover with egg, being sure to not let it pool. Sprinkle with sugar. Bake in a 425° preheated oven for 10–12 minutes, or until golden brown. Serve with pastry cream or whipped cream to dip.