7 tablespoons cold unsalted butter, cut into small pieces
1 large egg yolk
1/4 cup ice water
12 ounces cranberries
1/2 cup plus 1 tablespoon light brown sugar
1/2 cup plus 1 tablespoon granulated sugar
Finely grated zest of 1 orange
Finely grated zest of 1 lemon
1/2 cup fresh orange juice
1/8 teaspoon cinnamon
4 tablespoons plus 1 teaspoon unsalted butter
1/2 cup coarsely chopped walnuts
Vanilla ice cream, for serving
In a food processor, combine the flour, sugar, salt and cinnamon and pulse. Add the butter and pulse just until the mixture resembles coarse meal. Transfer the mixture to a bowl. Whisk the egg yolk with the ice water and add to the bowl; stir until an evenly moistened dough forms. Transfer the dough to a lightly floured surface and knead it several times. Pat the dough into a 6-inch disk, wrap it in plastic and refrigerate for at least 30 minutes.
In a medium saucepan, combine the cranberries with the brown and granulated sugars, the citrus zests, orange juice and cinnamon and bring to a boil. Lower the heat and simmer, stirring, until thickened, 8 to 10 minutes. Stir in the butter and transfer to a bowl to cool. Stir in the walnuts.
Preheat the oven to 375°. Butter a 10-inch fluted tart pan with a removable bottom. On a lightly floured surface, roll out the dough to a 12-inch round about 1/8 inch thick. Transfer the dough to the tart pan and fit it into the sides. Trim off the overhang. Prick the bottom of the tart shell all over and refrigerate until chilled.
Line the pastry with wax paper and fill with pie weights or dried beans. Bake the tart shell for 30 minutes, or until lightly golden around the edges. Carefully remove the paper with the weights and bake the shell for 5 minutes longer, or until dry on the bottom. Let cool slightly.
Spread the cranberry filling evenly in the tart shell and bake for about 25 minutes, or until the edge of the pastry is golden. Let the tart cool on a rack before unmolding. Serve warm or at room temperature, with vanilla ice cream.
The baked tart can be refrigerated overnight; rewarm in a 350° oven for 15 minutes before serving.