Preheat oven to 350 degrees F. Line a baking sheet with a silicone baking mat or parchment paper.

Sift flour, cocoa powder, baking powder, and salt into a mixing bowl. Set aside.

Combine chocolate and butter in a double boiler or a heat-proof bowl set over a pot of barely simmering water. Stir until melted and smooth. Remove from heat and set aside.

In a mixing bowl or the bowl of a stand mixer, beat together eggs, sugar, and vanilla until pale and creamy, about 8 minutes. Mix in melted chocolate mixture. Add dry ingredients and stir until just incorporated. Fold in chocolate chips.

Drop batter using a small cookie scoop by the scant tablespoonful onto cookie sheet, leaving two inches of space between cookies. The batter will be somewhat loose at this point, but shouldn’t be runny. It will thicken the longer it sits.

Bake for 7 to 8 minutes or until tops are shiny and cracked. Remove from oven and let cool on cookie sheet for 2 to 3 minutes, then transfer to a cooling rack to cool completely.

To dip, gently melt chocolate together with 1 tablespoon of shortening. You can use a microwave, heating on low power in short, 15 to 20 second bursts, or in a double boiler. Add more shortening as needed to thin out the chocolate to a dipping consistency, then dip half of each cookie into the melted chocolate. Place on a parchment lined baking sheet and top with sprinkles, if desired.

Cookies are best enjoyed within a day or two but will keep, covered in an airtight container, for up to a week.