In a medium bowl, combine the flour, sugar, baking powder, soda, salt, and cinnamon.
Fold in the egg and oil, stirring until just combined.
Fold in the zucchini and walnuts (if using).
Grease or place paper liners in a muffin tray.
Scoop batter and fill each cup about 1/2 full.
Bake in preheated oven, 350, for about 20-22 minutes.