Preheat Oven and Prep Pan
Preheat oven to 350°F (175°C).
Line a 12-cup muffin tin with paper liners or lightly grease.
Prep the Zucchini
Grate zucchini and squeeze out excess liquid using a towel or hands.
Mix Dry Ingredients
In a large bowl, whisk together flour, baking powder, baking soda, salt, and sugar if using.
Combine Wet Ingredients
In another bowl, whisk eggs, honey/maple syrup, melted oil, vanilla, lemon zest, and lemon juice.
Fold in shredded zucchini.
Bring It Together
Gradually add dry ingredients to wet mixture, stirring gently until just combined.
Fold in optional add-ins.
Bake
Spoon batter into muffin cups, filling ¾ full.
Bake 20–25 minutes, or until a toothpick comes out clean.
Cool in pan 5 minutes, then transfer to a wire rack.