Begin by softening your butter to room temperature. Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper or silicone mats.
In a large bowl, use an electric mixer to beat together the softened butter, granulated sugar, and brown sugar until light, fluffy, and pale, about 3-4 minutes.
Beat in the eggs, one at a time, ensuring each is fully incorporated before adding the next. Mix in the vanilla extract to create a smooth batter.
In a separate bowl, whisk together the all-purpose flour, baking soda, salt, and cocoa powder for even distribution.
Gradually add the dry ingredients into the wet ingredients, mixing on low speed or folding gently until just combined. Avoid overmixing.
Stir in the semi-sweet chocolate chips, milk chocolate chunks, and white chocolate chips until evenly distributed.
Use a cookie scoop or spoon to drop rounded tablespoons of dough onto prepared baking sheets, spacing about 2 inches apart. Bake for 10-12 minutes, until edges are set but centers remain soft.
Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely before enjoying.