•Unsalted butter, for coating the pan (if needed)
•3 cups all-purpose flour
•1 1/2 teaspoons baking powder
•1 1/2 teaspoons ground cinnamon
•1 teaspoon baking soda
•1/2 teaspoon freshly ground nutmeg
•1/2 teaspoon fine salt
•4 large eggs, at room temperature
•1 cup packed dark brown sugar
•1 cup granulated sugar
•1 cup vegetable oil
•2 teaspoons vanilla extract
•14 ounces zucchini (about 3 to 4 medium zucchini), ends trimmed, grated on the large holes of a box grater (about 3 cups)

Heat the oven to 350 degrees Fahrenheit and arrange two racks to divide the oven into thirds. Line two (12-well) muffin pans with paper liners. Alternatively, coat the wells with butter; set aside. Place the flour, baking powder, cinnamon, baking soda, nutmeg, and salt in a medium bowl and whisk to aerate and break up any lumps; set aside.

Place the eggs, sugars, oil, and vanilla in a large bowl and whisk until the eggs are broken up and the mixture is thoroughly combined. Using a rubber spatula, fold in the flour mixture until just combined. Fold in the zucchini until evenly mixed.

Fill the muffin wells about two-thirds of the way. Bake, rotating the muffin pans from front to back and top to bottom halfway through the cooking time, until the muffins are browned and a cake tester or toothpick inserted in the center comes out clean, about 25 minutes. Transfer the pans to wire racks and let cool for 5 minutes. Remove the muffins from the pans and cool completely.