Chocolate Thumbprint Cookies

In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter, sugar and brown sugar until light and fluffy.

Add the egg yolks, one at a time, beating between each addition, then add the vanilla extract.

In a separate small bowl, whisk together the flour, baking powder and salt.

Add the flour mixture to the stand mixer, beating just until the dough is combined. Cover the bowl with plastic wrap and refrigerate the dough for 30 minutes.

Preheat the oven to 325°F. Line two baking sheets with parchment paper or Silpat baking mats.

Scoop out portions of the dough and roll them into 1-inch balls. Space the balls 1 inch apart on the baking sheets, then using the back of a measuring spoon (or your thumb), make a deep indentation into each ball.

Bake the cookies for 10 to 12 minutes or until they are pale golden.

Remove them from the oven and allow them to cool for 5 minutes on the baking sheets before transferring them to a rack to cool completely. (If the indentations have disappeared, make them again while the cookies are still warm.)

While the cookies cool, make the chocolate filling.

Add the chocolate chips to a medium bowl.

In a separate medium microwave-safe bowl, combine the heavy whipping cream, corn syrup and butter. Microwave the mixture until it is steaming, about 1 minute, then pour it over the chocolate chips and let it sit for 5 minutes (without stirring).

Whisk the chocolate mixture until it is smooth. (If there are any chocolate chunks remaining, microwave the mixture for 15-second increments until smooth.)

Spoon about 2 teaspoons of the chocolate into each indentation and immediately top it with sprinkles. Allow the chocolate to sit until firm and shiny.