
Step 1 · Prep
Preheat the oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or grease well.
Step 2 · Mix the Dry Ingredients
In a large bowl, whisk together the flour, baking soda, baking powder, cinnamon, and salt.
Step 3 · Mix the Wet Ingredients
In a second bowl, whisk the eggs, sugar, oil, and vanilla until smooth. Stir in the grated zucchini.
Step 4 · Combine
Pour the wet mixture into the dry and fold together until just combined — a few streaks of flour are fine. Fold in the walnuts, if using.
Step 5 · Bake
Divide the batter among the muffin cups. Bake for 18-22 minutes, until a toothpick inserted in the center comes out clean.
Step 6 · Cool
Cool in the tin for 5 minutes, then transfer to a rack to cool completely.