3 cups all-purpose flour
1 1/2 teaspoons baking powder
1/4 teaspoon salt
1 cup butter, softened
1 cup sugar
1 large egg
1 teaspoon vanilla extract
2 teaspoons instant coffee
2 oz dark chocolate, melted
1. In a bowl, whisk together flour, salt, and baking powder.
2. Cream butter in an electric mixer until pale and fluffy. Gradually add sugar. Add egg and vanilla. Scrape down sides of bowl, mix until fully incorporated.
3. With the mixer on low speed, add dry mixture in a few batches. Mix until fully incorporated. Do not overmix! Dough should hold its shape but not be sticky.
4. Divide dough in half. Mix instant coffee powder into one half of dough and melted chocolate into the other. Mix the coffee half first to prevent melted chocolate from sticking to the bowl and being mixed in with the coffee dough.
5. Place each portion of dough on separate pieces of wax paper, and another piece of top of each. Roll doughs into roughly 9x14" rectangles, 1/4" thick. Try to make them the same shape. Refrigerate flat on a shelf or on a baking sheet for 1 hour.
6. Place coffee dough sheet directly on top of chocolate sheet, leaving one layer of wax paper underneath chocolate and one on top of coffee. Using a rolling pin gently press the two together.
7. Let dough come to room temperature. Cut one of the long sides to make a straight edge. Keep the straight edge towards you as you roll, so you'll be rolling away from your body and the straight edge will become the center of the log.
8. Using the bottom piece of wax paper as a guide, tightly roll the dough into a spiral. Be meticulous! If you take your time, these will turn out perfectly uniform.
9. Cover the dough in wax paper and refrigerate for 1 hour.
10. Heat oven to 350F. Line baking sheets with parchment paper. Cut dough log in half. Keep half cool in the fridge while you slice the other into 1/4" rounds. Bake for 10 minutes and repeat with remaining dough.