Instructions

• In a large bowl, whisk together 1 1/2 cups all-purpose flour, 1/2 cup confectioners' sugar, 1/2 teaspoon salt, 1/2 teaspoon ground cinnamon, and a pinch of ground ginger until evenly combined.
• Add 1/2 cup (1 stick) very cold, cubed unsalted butter to the dry ingredients. Using your fingertips (or a pastry cutter), work the butter into the flour mixture until the mixture looks like a mix of small pebbles and oatmeal-sized flakes.
• Add the lightly beaten egg yolk and, using a fork, stir and press the mixture together until it just holds when squeezed. The dough will be shaggy.
• Transfer the dough into a tart pan with a removable bottom (or into four mini tart pans with removable bottoms). Using your fingers, press the dough evenly into the bottom and up the sides of the pan(s). Smooth the surface and any seams.
• Freeze the assembled tart shell(s) for 1 hour to firm the dough. (This prevents excessive puffing while baking.)
• While the shells chill, chop 8 ounces dark chocolate finely and place it in a medium heatproof bowl.
• In a small saucepan over medium heat, bring 1 1/4 cups heavy cream just to a low simmer (small bubbles forming at the edge). Do not boil.
• Pour about half of the hot cream over the chopped chocolate and let sit for 1 minute. Whisk gently from the center outward to combine and melt the chocolate.
• Slowly add the remaining cream while continuing to whisk until the mixture is smooth and glossy.
• Add 1/4 cup (1/2 stick) unsalted butter, cut into cubes, and stir with a spatula until the butter is fully melted and incorporated. Set the ganache aside at room temperature until you are ready to fill the tart shell(s). It should be warm and pourable but not piping hot.
• Position a rack in the upper third of the oven and preheat the oven to 350°F (175°C). Butter a piece of foil (or four small pieces of foil if using mini pans) and place the butter-side down over the chilled tart shell(s) to weigh down the crust.
• Bake the covered tart shell for 20 minutes (about 16 minutes for mini tarts). Remove the foil and continue baking until the crust is golden brown and firm—about 15 more minutes for a whole tart (about 13 more minutes for mini tarts).
• Remove the tart shell(s) from the oven and cool completely on a wire rack.
• When the shell(s) are cool, pour or spread the ganache into the tart shell(s). Chill in the refrigerator to set: about 1 hour for a whole tart, or about 30 minutes for mini tarts.
• Choose one finishing option: a. For a simple finish, sprinkle a few flakes of flaky sea salt over the still-wet ganache. b. Or, to serve with whipped cream and berries: in a medium bowl, whip 1 cup heavy cream with 2 tablespoons confectioners' sugar using a handheld mixer until soft peaks form. Dollop or pipe the whipped cream onto the set tart and top with about 1 cup fresh raspberries.
• Serve immediately after finishing (if using whipped cream), or keep refrigerated until ready to serve.