Begin by preheating your oven to 350°F (175°C). Prepare a muffin tin by lining it with paper liners or greasing each cup with non-stick cooking spray.
In a large mixing bowl, thoroughly whisk together the all-purpose flour, cocoa powder, granulated sugar, brown sugar, baking powder, baking soda, and salt until well combined.
In a separate bowl, crack the egg and beat it lightly. Then add the milk, vegetable oil, and vanilla extract, mixing until smooth.
Pour the wet ingredient mixture into the bowl with the dry ingredients. Gently stir until just combined, being careful not to overmix.
Delicately fold in the semi-sweet, white, and dark chocolate chips until evenly distributed.
Spoon the muffin batter into the prepared muffin tin, filling each cup approximately ¾ full.
Place the muffin tin in the preheated oven and bake for 18-22 minutes. Check for doneness with a toothpick.
Once baked, remove the muffins from the oven and allow them to cool in the tin for about 5 minutes before transferring to a wire rack.
Notes
For a beautiful presentation, arrange the muffins on a rustic wooden board and drizzle with melted chocolate.