Hazelnut Linzer Thumbprints

Heat oven to 350 °F. Line baking sheets with parchment paper. In a medium bowl, whisk together the flour, baking powder, cinnamon, and salt. Using an electric mixer, beat the butter and brown sugar in a large bowl until light and fluffy, about 3 minutes. Beat in the egg. Reduce the mixer speed to low and gradually add the flour mixture, mixing until just incorporated. Roll the dough into 3/4-inch balls (about a level teaspoon each) and coat with chopped nuts. Transfer the balls to the prepared baking sheets, spacing them 2 inches apart. With a floured finger, make an indentation in the center of each ball, making sure not to go all the way through. Fill each cookie with 1/2 teaspoon preserves. Bake, rotating the position of the pans halfway through, until the cookies are golden brown around the edges, 14 to 16 minutes. Let cool on the sheet for 5 minutes, then transfer to a wire rack to cool completely.