Bittersweet Chocolate Peppermint Thumbprints
For the cookies
For the filling and assembly
Make the cookies
  1. Position a rack in the center of the oven and heat the oven to 350°F (180°C/gas 4). Line two cookie sheets with parchment or nonstick liners.
  2. Put the butter, brown sugar, cocoa powder, and salt in the bowl of a stand mixer fitted with the paddle attachment (or in a large bowl using an electric handheld mixer fitted with wire beaters). Beat on medium speed until well blended and smooth, about 1 minute. Add the vanilla and peppermint extracts and beat until well blended, about 1 minute. Add the flour and mix on low speed until a soft dough forms, about 1 minute.
  3. Using a 1-Tbs. mini scoop, shape the dough into balls and lightly roll them in your palms to smooth the edges. Arrange them about 1-1⁄2 inches (4 cm) apart on the prepared cookie sheets. Using a round 1⁄2-tsp. measure, press down into the middle of each mound to make a well that is almost as deep as the dough ball. If the dough sticks to the measuring spoon, dip the bottom of the spoon in a little flour. Small cracks in the ball are fine but if the edges break open, reroll and try again. The finished cookies will look better and hold the filling without leaking if the edges are smooth.
  4. Bake until the tops look dry, 14 to 16 minutes. Move the cookie sheet to a rack and let cool for about 5 minutes, then transfer the cookies to a rack to cool completely.
Make the filling and assemble
  1. Put the chocolate and butter in a small heatproof bowl and melt in the microwave or over a pan of simmering water, stirring until smooth. (This can also be done in the microwave.) Remove from the heat and set aside until cool and slightly thickened.
  2. Arrange the cooled cookies on a cookie sheet or sheet pan. Using a small spoon, drizzle the thickened and cooled chocolate into each indentation, filling just to the rim but not to overflowing. Alternatively, scrape the chocolate into one corner of a small zip-top plastic bag, press out the air, and seal. Cut off a small piece of the corner and pipe the chocolate into the indentations. Set the cookies aside until the chocolate filling is set but still tacky to the touch, about 10 minutes. Sprinkle the tops with the chopped peppermint candies. Let cool completely before stowing or serving.
Recipe Notes

Flavor swap

Chocolate–caramel: Omit the peppermint extract from the cookie dough and bake as directed. Instead
of the chocolate filling use quick caramel filling (see below). Replace the crushed peppermint candy topping with toasted, chopped nuts.

Caramel Filling
11 small (6 oz.) caramels (I use Kraft® brand), unwrapped
3 Tbs. heavy cream

In a small saucepan, combine the caramels and heavy cream. Set the pan over very low heat and cook, stirring constantly, until the caramels have melted and the mixture is smooth, about 2 minutes. (This can also be done in the microwave.)
Cover and refrigerate leftovers.

Make Ahead
The cookies can be baked and cooled, then layered between sheets of parchment or waxed paper in an airtight container and stowed at room temperature for up to 5 days or frozen for up to 3 months before thawing at room temperature and filling.

The chocolate filling can be prepared and refrigerated for up to 2 weeks. Gently reheat in the microwave or on top of the stove and fill the cookies while the chocolate is still warm.

The filled cookies can be stowed at room temperature for up to 3 days. To keep the cookies looking their best, arrange them on a half sheet pan in a single layer and cover the pan tightly (avoiding the cookie tops) with plastic.

Shaping the dough and forming the indentation
Scoop the dough with a 1-Tbs. mini scoop, then release it into your hand.

Form the dough into a smooth ball, rolling it between the palms of both hands (there’s no need to flour your hands).

Once all the dough balls have been rolled, use a 1⁄2-tsp. measure to press down gently into the center of the ball, going almost to the bottom. Dip the measure in flour if it starts to stick to the dough.

If big cracks form as you press into the dough ball, reroll the dough and start again.