- In a large non-stick skillet, bring the sugar and water to a boil. Cook without stirring until the mixture turns an amber colour. Off the heat, add the cream and mix thoroughly.
- Add the apple pieces and stir well to coat with the caramel. Beware of splattering. Cover and let simmer over medium-low heat for about 12 minutes or until the apples are soft and well-caramelized. Let cool.
- With the rack in the middle position, preheat the oven to 400°F (200°C). Line two baking sheets with parchment paper.
- On a floured work surface, roll out the puff pastry into two 10-inch (25 cm) squares. Brush with the cream and sprinkle with the sugar. Cut each pastry square in half, then each rectangle into four pieces. With a spatula, place the pastry rectangles on the baking sheets. Refrigerate until ready to bake.
- Bake, one sheet at a time, for 18 to 20 minutes or until the pastry is golden brown. Let cool completely.
- In a bowl, whip all the ingredients with an electric mixer until soft peaks form. Keep in the refrigerator until ready to serve (see note).
- Top each pastry rectangle with 1/4 cup (60 ml) of the mascarpone cream. Place 3 apple pieces on the cream. Add 2 tbsp (30 ml) of cream and top with another puff pastry. Add another 2 tbsp (30 ml) of cream and garnish with the remaining apple pieces. Repeat with the remaining ingredients.
Do not whip the cream more than 1 hour before serving. It may fall slightly if made too far in advance.