1-First Step: Preheat and Prep: Set oven to 425°F (220°C). High heat creates domed tops. Whisk dry ingredients (flour, sugar, cocoa, baking powder, baking soda, salt) in a large bowl. This prevents lumps later.

2-Second Step: Mix Wet Ingredients: In another bowl, beat eggs lightly. Stir in buttermilk, oil, and vanilla until combined. The mixture should look smooth. Avoid overmixing to keep muffins tender.

3-Third Step: Combine Wet and Dry: Pour wet into dry. Stir gently with a spatula, just until flour disappears. Batter will be thick and lumpy, perfect for muffins. Overmixing leads to tough texture.

4-Fourth Step: Fold in Chocolate Chunks: Add 1 1/2 cups chocolate chunks. Fold 4-5 times to distribute evenly. Reserve a handful for topping. This ensures chunks throughout without sinking.

5-Fifth Step: Fill Muffin Cups: Scoop batter into liners, filling 3/4 full. Use an ice cream scoop for even portions. Sprinkle extra chunks on top. Tap tin to settle batter.

6-Sixth Step: Bake: Bake at 425°F for 5 minutes, then reduce to 350°F without opening door. Continue 15-18 minutes. Test with toothpick; moist crumbs mean done. Cool in tin 5 minutes, then on rack.