Raspberry Palmiers

Pulse flour and salt in a food processor until combined. Add butter and pulse until mixture resembles coarse crumbs. Add sour cream and pulse until mixture holds together when pinched. Knead dough on a work surface to bring together, then flatten into an 8-by-6-inch rectangle. Wrap in plastic and refrigerate until firm, at least 1 hour and up to overnight.

Preheat oven to 375 degrees. In a small bowl, stir together sugar and cinnamon; sprinkle half of mixture evenly on work surface. Let dough stand at room temperature until pliable. Cut in half; place one half of dough on sugared surface. With a floured rolling pin, roll into a 14-inch square. Spread half of jam onto dough, leaving a 1/4-inch border all around. Starting from one side, tightly roll dough toward center, incorporating sugar. Repeat, rolling other side to meet first roll in middle. Freeze 15 minutes.

With a serrated knife, cut dough crosswise into 1/4-inch-thick slices. (Refrigerate dough as needed if it gets too soft to slice.) Arrange slices 2 inches apart on parchment-lined baking sheets.

Bake 10 minutes. Carefully flip palmiers with an offset spatula and bake until golden, about 6 minutes more. Let cool on sheets 1 minute, then transfer to a wire rack; let cool completely. Repeat with remaining sugar mixture and dough. Cookies can be stored in an airtight container, between sheets of waxed paper, up to 1 week.