"Cantucci are typical Tuscan cookies, traditionally served with vin santo or red wine. They are also known as Italian biscotti because they are twice (bis) cooked (cotti). This version with dark chocolate is even yummier than the original!"
Preheat oven to 350 degrees F (175 degrees C). Line a baking sheet with parchment paper.
Combine sugar, eggs, and vanilla extract in a large bowl; beat with an electric mixer until frothy. Add flour and baking powder and mix well. Fold in chocolate pieces until a sticky dough forms. Separate dough into 2 portions and shape each portion into a long, thick log. Place logs 2 inches apart on the prepared baking sheet.
Bake logs in the preheated oven until golden brown, 15 to 20 minutes.
Remove logs from the oven and cool until easily handled, about 5 minutes. Transfer to a cutting board; slice logs diagonally into 3/4-inch slices using a serrated knife.
Return cantucci slices to the baking sheet and return to the oven. Turn off oven and allow cantucci to dry in the warm oven for 30 minutes. Cool to room temperature, about 10 minutes, before serving.