Preheat the oven to 400°F / 205°C. Bake the pastry on a parchment-lined baking sheet for 10-12 minutes, until light golden.
Break the pastry into pieces in a 9 × 13in / 23 × 33cm baking dish and scatter with ½ cup of chopped hazelnuts, ½ cup of sliced almonds, ½ cup of chopped pistachios, ½ cup of shredded coconut, and ½ cup of raisins.
Bring 2 cups of milk, ½ cup of sugar, and 1 teaspoon of vanilla extract to a simmer and cook for about 3 minutes. Pour the hot milk over the pastry.
Whip 1 cup of heavy cream to stiff peaks, 5-7 minutes. Spread it over the top and sprinkle with 1 tablespoon of dark brown sugar.
Broil on the center rack for 3-6 minutes, watching closely, until the top is golden.
