A dollop of lemon curd or raspberry jam tops these buttery, lemon thumbprint cookies. The result is a colorful and refreshing addition to your holiday cookie assortment.
Preheat the oven to 350°F. Lightly grease two baking sheets, or line with parchment.
In a large bowl, beat the butter, sugar, lemon rind or oil, vanilla, and salt until very light.
Beat in the egg.
Add the flour, stirring until well blended.
Use a teaspoon cookie scoop (about 2 measuring teaspoons) or tablespoon cookie scoop (about 4 measuring teaspoons) of dough for each cookie. Scoop cookies onto the baking sheets, leaving 2" between them.
Use your fingertip (for smaller cookies) or thumb (for larger cookies) to put an indentation into the center of each.
Bake the cookies for 12 to 14 minutes. Remove them from the oven.
Let the cookies cool for about 5 minutes to firm up, then move them to a rack to finish cooling.
Once the cookies are cool, fill the indentation with lemon curd or raspberry jam, using about 1/4 teaspoon for each teaspoon-scoop cookie, or 1/2 teaspoon for each tablespoon-scoop cookie.
Store thumbprint cookies, well wrapped, at room temperature for several days. Freeze for longer storage.
For an extra decorative touch, make a simple glaze to pipe or drizzle over the cookies: Sift 1 cup (113g) confectioners' sugar into a medium bowl. Gradually add 2 tablespoons (28g) fresh lemon juice, stopping when your glaze is thin enough to drizzle but thick enough to hold its shape (you may have to adjust with additional sugar or juice to reach the ideal consistency). Drizzle it over thumbprints with a spoon or fork, or transfer it to a pastry bag or plastic bag with the corner snipped and pipe decorations.
