Preheat oven to 350 degrees and grease or line a muffin tin with paper liners.
In a large bowl, whisk together flour, sugar, cinnamon, baking powder, baking soda, and salt.
Whisk eggs into oil, then stir in vanilla. Stir wet ingredients into dry ingredients until just combined (mixture will be very thick and somewhat dry).
Fold zucchini into batter until incorporated.
Fill muffin tins 3/4 full.
Bake for 20-22 minutes until an inserted toothpick comes out clean.
Store at room temperature in airtight container up to 5 days or wrap individually with plastic wrap and store in the fridge or freezer up to 3 weeks. Serve at room temperature or pop them in the microwave for a few seconds and slather on a bit of butter.