1Heat the oven to 375°F and arrange a rack in the middle. Melt chocolate in a small saucepan over low heat, stirring occasionally; remove from heat and set aside.
2Whisk together flour, cocoa powder, baking soda, salt, and espresso powder in a medium mixing bowl to aerate and break up any lumps. Set aside.
3Combine butter and sugar in the bowl of a stand mixer fitted with a paddle attachment and cream by mixing on medium speed until light and fluffy, about 3 to 5 minutes. Add vanilla extract and blend well. Scrape down the bowl and add eggs one at a time, mixing well after each addition.
4Put mixer on low and add melted chocolate. Add flour mixture and mix until just incorporated. Drop dough by rounded tablespoons onto an ungreased baking sheet, then press half a caramel into the center of each cookie. Bake until cookies are puffed and set, about 8 minutes. Transfer to a rack and let cool slightly.