1) Preheat the oven to 425 degrees F.
2) Line a baking sheet with parchment paper or foil. Stir the mascarpone cheese with a spoon to warm it up and make it creamier.
3) Place the sheet of puff pastry on the baking sheet. Poke it a few times all over with a fork.
4) Spread the mascarpone cheese on the pastry, leaving a 1-inch border. Spread it evenly all over - you don’t want too much in the center, or the middle won’t cook.
5) Layer on the sliced apples. Drizzle with the honey. Sprinkle with a pinch of salt and pepper. Top with the chopped pistachios.
6) Bake at 425 degrees F for 20 to 25 minutes until the pastry is golden and crisp. Serve immediately.