3 cups all-purpose flour
1½ tsp. baking powder
1½ tsp. baking soda
1½ tsp. kosher salt
3 cups sugar
8 oz. unsalted butter, diced
1 whole vanilla bean, split and scraped
8 oz. chocolate chips
Put the flour, baking powder, baking soda, salt, and sugar in the bowl of a stand mixer with a paddle attachment and mix on low speed to combine. Add the butter and beat on medium speed until the mixture resembles a coarse meal.
Whisk the eggs together in a separate bowl. Slowly add them to the flour mixture, beating until they are just blended. Place the dough out onto a work surface, cover with plastic wrap, and let rest for 15 minutes.
Preheat oven to 350°F and line a baking sheet with parchment paper.
Divide the dough into three equal parts. Shape into three slightly flattened logs that are approximately three inches wide by 15 inches long. Brush the tops with water and coat them with sugar. Bake for 45 minutes, or until golden brown. Reduce the oven temperature to 250°F.
Let the logs cool slightly. Using a serrated knife, cut the logs on the diagonal in half-inch slices. Bake the slices for 15 to 20 minutes, until brown and crispy. Cool. Store in an airtight container. They will keep for one week.