1Whisk together flour, baking powder, baking soda, and cornstarch in a medium bowl. Set aside.
2Cream together brown sugar, granulated sugar, and butter in a large bowl until light and fluffy.
3Beat in eggs one at a time, then add vanilla extract. Mix for 3-4 minutes until pale and sugar is incorporated.
4Gradually mix in dry ingredients until just combined; do not overmix.
5Stir in chocolate chips.
6Scoop 3-4 tablespoon-sized balls of dough onto a baking sheet lined with parchment paper. Leave the dough balls slightly rough and stacked, with a rustic texture. Place 4 cookies on each pan, leaving 4 inches of space between each one.
7Bake at 350°F (180°C) for 13-16 minutes, or until edges are lightly golden brown.
8Remove from oven and let cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely.