1 1/4 (1/2 cup plus 2 tablespoons) sticks cold unsalted butter, cut into pieces
1 1/4 cups all-purpose flour
1 rounded 1/4 teaspoon salt
2 tablespoons beaten egg
1 cup raspberry jam
Preheat oven to 400¿ F.
Reserve 1/4 cup almonds in a bowl for topping. Finely grind remaining 1 3/4 cups nuts with sugar in a food processor.
Add butter, flour, and salt, then process until mixture resembles sand.
Add 1 cup flour mixture to reserved almonds. Add beaten egg to remaining flour mixture and pulse until mixture begins to clump together.
Transfer mixture from processor to a 9- by 1-inch round tart pan with a removable bottom. Press mixture with floured fingers onto bottom and up side of pan and bake in middle of oven 15 minutes. Meanwhile, stir raspberry jam to loosen. Rub reserved almond mixture in bowl between your palms to form small clumps.
Remove tart shell from oven and spread jam over bottom. Sprinkle almond mixture over jam and bake tart 15 minutes. Cool tart in pan on a rack. Loosen side of pan with a knife, then remove it.
Cook's note: you can make tart 1 day ahead, then cool it before chilling, covered. Bring to room temperature before serving.