Preheat oven to 350°F and line two baking sheets with parchment paper.
Whisk together the flour, cocoa powder, baking soda, and salt in a medium bowl.
In a large bowl, beat the butter, brown sugar, and granulated sugar until creamy and smooth, about 2-3 minutes.
Add the eggs and vanilla extract, beating until well combined and fluffy.
Gradually mix in the dry ingredients until just combined, then fold in both the semi-sweet and white chocolate chips.
Drop rounded tablespoons of dough onto the prepared baking sheets, spacing them 2 inches apart.
Bake for 10-11 minutes until the edges are set but centers still look slightly soft and underdone.
Let cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.