Preheat oven to 350˚F (180˚C). Line a large baking sheet with parchment.
In a large bowl, beat together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then the vanilla extract. Slowly add baking powder, salt, and flour until dough comes together. Fold in chocolate chips.
Divide the dough into 2 equal pieces. Form one of the pieces into a log about 12 inches (30 1/2 cm) long. Place near the edge of the prepared baking sheet and gently flatten until about 3 inches (7 1/2 centimeters) wide and 1/2 inch (1 centimeter) thick. Repeat with other half of the dough.
Bake in preheated oven until set and the bottom is golden brown, about 25 minutes. Remove from oven and allow sit at room temperature for 20 minutes until cool to touch.
Use a serrated bread knife to cut each log on the diagonal into 1/2-3/4 inch (1.25- 2 centimeter) thick slices. Return slices to baking sheet, cut side down. Bake for another 10-15 minutes, until crisp.
Allow to cool to room temperature and store in airtight container for up to about 2 weeks.