Lemon or Pink Grapefruit Tart with Meringue

For the Dough

• 2½ cups (300 g) all-purpose flour
• Pinch of salt

Make the dough. This is ideally done in a food processor, but you can do it in a bowl as long as your hands are cold: Combine the flour, salt, and sugar. Add the butter and pulse until the dough looks like coarse crumbs. Add the egg and a few drops of ice-cold water. Pulse until the dough just comes together. Shape the dough into a flat slab, wrap it in plastic wrap, and chill in the fridge for