Preheat the oven to 350°F (175°C).

In a bowl, mix together the flour, cocoa powder, baking soda, and salt.

In another bowl, cream the softened butter and sugar together.

Add the egg and vanilla extract to the butter mixture and mix well.

Gradually blend the dry ingredients into the wet mixture until combined.

Fold in the chocolate chips.

Drop spoonfuls of dough onto a baking sheet lined with parchment paper.

Bake for 10-12 minutes or until set.

Allow to cool on the baking sheet for a few minutes before transferring to a wire rack.