Preheat oven to 375º F. Grease 10 muffin tins with oil or cooking spray.
In a medium-sized bowl, sift together the flour, cinnamon, nutmeg, baking powder, baking soda, and salt. I like to add a heaping teaspoon of cinnamon because I love the flavor.
In a large bowl, mix the egg, sugar, applesauce, oil, yogurt, and vanilla until well incorporated. Gradually mix the flour to the wet ingredients. I like to add the flour in three batches.
Gently fold in the zucchini, lemon zest, poppy seeds, and walnuts.
Spoon the mixture into the muffin pan until you fill up 10 of the tins.
Bake for about 20-23 minutes, or until a toothpick comes out cleanly.
Let the muffins cool for about 10 minutes.
Store the muffins in an airtight container. If you haven't finished all of them in about a day or two, refrigerate them.