Preheat oven to 350°F and line baking sheets with parchment paper.
Cream butter and 1 cup sugar until light and fluffy.
Add eggs one at a time, beating after each, then stir in vanilla.
In a separate bowl, whisk together flour, baking powder, salt, cocoa powder, and espresso powder.
Mix dry ingredients into wet just until combined. Do not overmix.
Roll dough into 1-inch balls and coat in remaining ¼ cup sugar.
Place dough balls 2 inches apart on sheets.
Bake for 10-12 minutes until tops crack slightly.
Immediately press a chilled caramel kiss into the center of each cookie.
Cool on sheet for 5 minutes, then transfer to wire rack.
Notes
Chill caramel kisses ahead to prevent melting when pressing into hot cookies. Store leftovers in airtight container at room temp or freeze up to 2 months.