Preheat Oven & Prepare Muffin Pan:

• Preheat the oven to 375°F (190°C).
• Line a muffin tin with paper liners or grease it lightly.

Mix Dry Ingredients:

• In a large bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt.

Mix Wet Ingredients:

• In another bowl, whisk melted butter, granulated sugar, and brown sugar until combined.
• Add eggs one at a time, mixing well.
• Stir in vanilla extract and buttermilk.

Combine Wet & Dry Mixtures:

• Gradually add dry ingredients to the wet ingredients, stirring until just combined.
• Fold in melted dark chocolate.
• Gently fold in semi-sweet and white chocolate chips.

Bake the Muffins:

• Divide the batter evenly into the muffin cups, filling each about ¾ full.
• Bake for 18-22 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.

Cool & Serve:

• Let muffins cool in the pan for 5 minutes before transferring them to a wire rack.
• Enjoy warm or at room temperature!