1 cup (2 sticks) unsalted butter, cut into 1/2-inch pieces
3 large egg yolks
1/4 cup chilled Vin Santo (traditional Italian wine)
2 cups best-quality cherry jam
Freshly ground pepper
In the bowl of a food processor, combine flour, sugar, salt, and zest; pulse 2 or 3 times to mix. Add butter; pulse until mixture resembles coarse meal.
In a small bowl, beat egg yolks with Vin Santo. With machine running, add to flour mixture; process until dough comes together and pulls away from sides of bowl, 5 to 6 seconds. Turn dough out onto work surface; shape into disc. Cover with plastic wrap, and refrigerate for at least 30 minutes.
Preheat oven to 425 degrees. In a small bowl, thin the jam with hot water a teaspoon at a time, stirring until smooth; season with a dash of pepper. Mix well. Set aside.
Remove dough from refrigerator. On a lightly floured work surface, roll out dough to a circle 14 inches in diameter. Fit dough into a 12-inch fluted round tart pan with a removable bottom, pressing gently into sides and bottom. Trip excess pastry by rolling the rolling pin across top. Spread jam mixture over dough.
Bake until filling is glossy and dough is deeply golden, 25 to 30 minutes. Transfer to a wire rack and cool for several minutes. Serve warm.