Preheat oven to 350°F and line a baking sheet with parchment paper.

In a medium bowl, sift together the flour, cocoa powder, baking soda and salt. Set aside.

n a large bowl or stand mixer, cream together the butter and light brown sugar until smooth and creamy. Beat in the eggs one at a time, followed by the vanilla extract.

Gradually add in the dry mixture and mix until combined. The batter should be thick and slightly sticky.

Using a spoon or cookie scoop, drop 1-inch balls of dough onto the prepared baking sheet. Bake for 8-10 minutes or until edges are set but centers are still soft.

Allow cookies to cool on baking sheet for 5 minutes before transferring to a cooling rack to cool completely.