Preheat the oven to 425°F. Lay the puff pastry on a parchment-lined baking sheet. Use a fork to prick the dough, leaving the edges free. Beat the egg with 1 tbsp water and brush over the dough. Bake for 15 min., or until golden brown. (For best results, allow cooked dough to cool 15 min., before assembling tart.) If dough puffs too much, use fingers to press it flat.
While pastry bakes hull and slice the strawberries. In a large bowl, blend mascarpone and honey with a rubber spatula. If mixture is too thick, add a few drops of warm water.
Spread lemon curd over the cooked pastry and top with the mascarpone-honey mixture. Arrange the raspberries and strawberries alternately in wide stripes over the mascarpone. Finely chop the mint and sprinkle over the tart.