Step 1

Preheat oven to 375 F and line baking sheets with parchment paper.

Step 2

In the bowl of a stand mixer fitted with the paddle attachment, cream the butter and sugar until light and fluffy (2-3 minutes).

Step 3

Add the egg and vanilla, and mix well to combine.

Step 4

Add the baking powder, salt, and mix to combine.

Step 5

Add the flour in a couple of batches, mixing briefly between each addition. When all the flour has been added, scape the bowl and mix by hand briefly to make sure everything is well incorporated.

Step 6

Shape the cookies by taking about a tablespoon of dough and rolling it into a ball. Using the back of a 1/4 teaspoon, or something of similar size, make an indentation in the ball of dough, flattening it slightly.

Step 7

Repeat for all of the dough, and bake for 8-10 minutes. Note: the cookies will still be quite pale when done.

Step 8

Remove from the oven, and allow the cookies to partially cool on the baking sheet before transferring to a baking rack to finish cooling.

Step 9

Meanwhile, make the ganache by heating the cream in a small saucepan or the microwave until just starting to bubble (not actually until boiling). Remove from the heat and pour over the chopped chocolate.

Step 10

Let the mixture sit, undisturbed, for several minutes.

Step 11

Stir the chocolate into the cream, adding the salt, and vanilla extract. Keep stirring until the mixture turns smooth and glossy.

Step 12

Let your ganache sit and cool down a bit to thicken up before filling the cookies. A thin ganache will pour into the indentations with a very smooth, flat top, and a thicker ganache will have a bit more texture on top.

Step 13

Fill all of the cookies and allow them to sit flat until the ganache has set.

Step 14

If you'd like to add sprinkles to your cookies, do it right away, before the ganache sets up.