Yields 4 dozen cookies
- 2 1/2 cups all-purpose flour
- 1/2 teaspoon salt
- 1 cup (2 sticks) unsalted butter, softened
- 1 cup sugar
- 1 large egg
- 1 teaspoon pure vanilla extract
- 1/3 cup raspberry jam
- 1/3 cup chopped walnuts
In a bowl, whisk together flour and salt. Beat butter and sugar with an electric mixer until very pale and fluffy, about 4 minutes, then beat in egg and vanilla. At low speed, mix in flour mixture just until a dough forms. Wrap dough in plastic and chill until firm, about 1 hour.
Preheat the oven to 350 degrees with racks in the top and bottom thirds. Line 2 large baking sheets with parchment paper. Pinch off heaping teaspoon-size balls of dough and roll into balls. Place balls on the prepared baking sheets, about 2 inches apart and flatten slightly with the palm of your hand. Bake them until they are puffed, but not browned, about 8 minutes.
Remove baking sheets from oven and carefully make a small crater in the middle of each cookie using a teaspoon-size measuring spoon. Fill each crater with 1/4 to 1/2 teaspoon jam and some walnuts in the preserves. Bake the cookies until they are golden brown on the bottom and edges, about 8 minutes more. Cool the cookies on the baking sheets for 5 minutes, then transfer them to racks and cool completely. Store in air tight container at room temperature.