Preheat oven to 350°F. Mix together flour, baking powder, baking soda, salt and cinnamon. In another bowl beat eggs, sugar, vanilla and oil. When well beaten add zucchini and mix well. Slowly add flour mixture, and then stir in walnuts.
Equally divide mixture among two lined muffin pans.
Bake until inserted toothpick comes out clean (about 20 minutes).