Preheat the oven to 160°C (320°F). Roll out the KOUROU dough and cut it into 12 square pieces, leaving a small border around the edges. Use a cookie cutter to cut small heart shapes from the leftover border dough. Place 1 teaspoon of strawberry jam in the center of each square. Fold three corners towards the center to create a small envelope shape (as shown in the video). Arrange the envelopes on a baking tray and brush them with the beaten egg for a glossy finish. Stick a small heart in the center of each envelope and brush it with egg as well. Bake at 160°C (320°F) for about 15-20 minutes or until golden brown and crispy.