Preheat your oven to 350°F (175°C).
Line several baking sheets with parchment paper. 2.
In the bowl of a stand mixer fitted with the paddle attachment, cream the room temperature butter with the granulated and brown sugars on medium speed until light and fluffy, about 3-4 minutes. 3.
Add the eggs one at a time, mixing well after each addition. Scrape down the sides of the bowl as needed to ensure everything is incorporated. 4.
Reduce the mixer speed to low.
Add the pastry flour, bread flour, salt, baking powder, and baking soda.
Mix until just combined—do not overmix.
Stir in the vanilla extract and the chopped chocolate. 5. For large 5-inch cookies, use a 4-ounce scoop. For smaller 1½-inch cookies, use a 1¼-ounce scoop. Portion the dough onto the prepared baking sheets, leaving at least 2 inches of space between each cookie. 6.
Bake until the edges are golden brown but the centers are still soft. This will take about 20 minutes for large cookies or 15 minutes for smaller ones. 7.
Let the cookies cool on the baking sheets for 5 minutes before carefully transferring them to a wire rack to cool completely.
Don't skimp on the chocolate! Use a high-quality chocolate bar and chop it by hand. This creates a mix of fine shards and large chunks for the perfect melt.