Thaw puff pastry. Arrange puff pastry slices, slightly overlapping, on a piece of baking paper, cover with another piece of baking paper and roll out until slightly larger than a rectangular tart pan (30 x 22 cm) (approximately 12 x 9 inches) and line pan with it, making small edge all around. Prick several times with a fork and refrigerate, covered, for 1 hour.
Peel and core apples, cut into thin slices. Spread apple slices on the pastry and sprinkle with 2 tablespoons of sugar. Bake in preheated oven at 200°C (gas mark 3-4, fan oven 180°C) (approximately 400°F) for about 20 minutes. Remove from the oven and cool.
Clean raspberries and arrange on top of apples. Combine apple juice with remaining sugar. Prepare pie glaze (or cornastarch) according to package instructions with juice and brush raspberries with the mixture. Let dry. Garnish with mint leaves and serve.