Ingredients
Equipment
Method
Preheat and prep
- Preheat the oven to 350°F and line a 12-cup muffin tin with liners. Arrange the rack in the center so the tops bake and crack evenly.
Mix dry ingredients
- Whisk all-purpose flour, unsweetened cocoa powder, baking soda, baking powder, and salt together in a large bowl. Whisk until the cocoa looks evenly distributed with no dry streaks.
Mix wet ingredients
- Beat eggs, granulated sugar, vegetable oil, sour cream, and vanilla extract together until smooth in a separate bowl. Beat just until the mixture turns glossy and uniform.
Combine batter
- Stir the wet mixture into the dry mixture until just combined. Stop as soon as you no longer see dry flour to keep the muffins fudgy.
Add zucchini and most chips
- Fold in grated and squeezed-dry zucchini and 3/4 cup of the semi-sweet chocolate chips. Fold gently so the batter stays thick and does not overmix.
Fill and top
- Divide the batter evenly among the muffin cups, filling each about 3/4 full, then top with the remaining chocolate chips. Place the chips on top so they melt into glossy pools during baking.
Bake
- Bake at 350°F for 20–22 minutes, until a toothpick comes out with a few moist crumbs—do not overbake. For the darkest, most fudgy centers, pull them when the tops look set and slightly cracked.
Cool
- Cool in the pan for 5 minutes, then transfer to a wire rack. Let them cool at least 10 minutes so the molten chip pocket firms up slightly without drying out.
Notes
Key pro tip: squeeze the grated zucchini very dry—excess moisture prevents a fudgy crumb and can make the tops steam instead of crack. Store muffins in an airtight container at room temperature for 2 days or refrigerate up to 4 days; rewarm 10–15 seconds in the microwave for a softer center. Freezing is yes: freeze in a sealed bag up to 2 months and thaw overnight in the fridge. For a dairy-light option, swap sour cream with an equal amount of plain Greek yogurt for similar moisture and tang.