Preheat your oven to 350°. Finely grate your zucchini (I don't bother peeling because I like the green color of the strands throughout the muffins) using a hand grater or a food processor if you're wise.
In a large bowl, mix the melted butter and sugar until well combined.
Add your eggs and vanilla (only one egg shown) and mix for 30 seconds.
Whisk the flour, baking soda, salt, cinnamon, and nutmeg in a separate medium bowl and add them to the wet ingredients, mixing just to combine.
Stir in the zucchini followed by the walnuts. Do not overmix.
Divide the batter evenly among a paper-lined muffin tin. I fill mine to the top so I was only able to make eleven muffins out of the batter.
Bake for about 22 minutes, or until a toothpick inserted in the center of one of the muffins comes out clean.