Preheat the oven to 350°F (175°C)
Line a baking sheet with parchment paper
Mix flour, cocoa powder, baking soda, and salt in a bowl
Cream butter, granulated sugar, and brown sugar in another bowl
Add eggs and vanilla extract to the butter mixture
Gradually add the dry ingredients to the wet ingredients
Stir in chocolate chips or chopped chocolate
Scoop dough onto the prepared baking sheet
Flatten the dough slightly if needed
Bake for 8 to 12 minutes
Remove from the oven and let cool on the baking sheet for a few minutes
Transfer cookies to a wire rack to cool completely