How to Make Thumbprint Cookies
- Preheat oven to 350 degrees. In a large bowl, using an electric mixer, beat butter and sugar until smooth. Add egg, and beat until completely combined. With mixer on low, add flour, and mix just until incorporated.
- Shape dough into 1-inch balls (about 2 tablespoons each). Place on baking sheets, at least 3 inches apart.
- Moisten thumb with water, and gently press the center of each ball, making an indentation about 1/2 inch wide and inch deep. Spoon about 1/2 teaspoon into each indentation. Bake until cookies are golden brown around edges, 18 to 20 minutes. Transfer to a wire rack, and let cool completely. If storing, place in an airtight container at room temperature, up to 2 days or freeze for longer storage.