Everyone loves a crisp cookie with a rich and creamy filling, and thumbprint cookies are an easy alternative to sandwich cookies. We love this version, which is filled with a decadent chocolate ganache that comes together easily in the microwave. Crushed peppermint candies make a pretty holiday topper, but you could also decorate the cookies with chopped toasted nuts, shredded coconut, or a drizzle of royal icing. The thumbprint dough can be made a day ahead and the cookies can be stored at room temperature for up to two days.
1 cup unsalted butter, softened
3/4 cup powdered sugar
1/4 cup packed light brown sugar
1 large egg yolk
1 teaspoon vanilla extract
3 cups all-purpose flour
1/2 teaspoon kosher salt
1/2 teaspoon baking powder
3/4 cup semisweet chocolate chips
3 tablespoons heavy cream
1/4 cup crushed hard peppermint candies (about 12 candies)
How to Make It
Preheat oven to 375°F with oven racks in the top third and bottom third of oven. Beat butter and both sugars with an electric mixer on medium speed until smooth, about 1 minute. Add egg yolk and vanilla, and beat on low speed just until incorporated. Whisk together flour, salt, and baking powder in a small bowl, and gradually add to butter mixture, beating on low speed just until incorporated after each addition.
Drop dough by tablespoonfuls 1 inch apart onto parchment paper-lined baking sheets. Press your thumb or the end of a wooden spoon into each ball, forming an indentation.
Bake in preheated oven until cookies are set and beginning to brown, about 12 minutes, switching pans top rack to bottom rack halfway through baking. Cool on pans on wire racks 5 minutes; remove cookies to wire racks, and cool completely, about 30 minutes.
Combine chocolate chips and cream in a microwave-safe bowl, and microwave on MEDIUM (50% power) until melted and smooth, about 1 1/2 minutes, stirring every 30 seconds. Cool 5 minutes. Fill each indentation with about 1/2 teaspoon of the ganache. Sprinkle cookies evenly with crushed peppermints, and let stand 15 minutes before serving.