Ingredients

• For the crust:
• 1 1/2 cups all-purpose flour
• 3/4 cup (6 ounces or 1 1/2 sticks) unsalted butter, cut into small pieces and chilled
• 3/4 cup powdered (confectioners) sugar
• 1/2 teaspoon salt
• For the filling:
• 10 ounces bittersweet (not unsweetened) or semisweet chocolate, chopped
• 1/4 cup Irish whiskey or chocolate liqueur
• 1 1/2 teaspoons vanilla extract
• 1 1/4 teaspoons instant coffee crystals (optional)
• Pinch of salt
• 4 large eggs, separated
• 1/2 cup granulated sugar
• To serve (optional): Sweetened whipped cream or ice cream
• Special equipment:
• 9-inch tart pan with removable bottom

Serves 8