Add flour, cocoa powder, instant coffee, sea salt and baking powder to a medium bowl, whisking to combine. Add butter and sugar to the bowl of a stand mixer fitted with the paddle attachment. Cream at medium speed until fluffy (about 2 minutes). Mix in the egg and vanilla extract, scraping down the sides as needed. In 3 additions, mix in the dry ingredients just until combined. Don’t overmix here. Scrape cookie dough on to a lightly floured work surface, and gently roll into a log that’s 2-inches in diameter. Cover the entire surface of the dough with sprinkles, and roll back and forth several times to make them stick. Wrap dough tightly in plastic, and chill in the freezer for 1 hour.**