Preheat the oven to 350°F (175°C).
Prepare the muffin tin by lining it with paper liners or lightly greasing it.
In a large bowl, whisk together the dry ingredients: flour, cocoa powder, sugar, baking powder, baking soda, and salt.
In a separate bowl, combine the wet ingredients: egg, milk, oil, and vanilla extract.
Pour the wet ingredients into the dry mixture and stir until just combined.
Fold in the chocolate chips gently.
Spoon the batter into the prepared muffin tin, filling each cup about 3/4 full.
Bake in the preheated oven for 18-20 minutes.
Allow the muffins to cool in the pan for 5 minutes before transferring to a wire rack.
Enjoy your chocolate muffins warm or at room temperature!
