Preheat a cast iron Dutch oven with legs by placing 15 hot coals on the top of the lid, and 7 hot coals evenly spaced under the pot to bring the Dutch oven to 350°F. On a colder day, add another briquette or so.
Grease the bottom of the Dutch oven with softened butter.
Mix zucchini, coconut sugar, melted butter, vanilla and eggs in a large bowl.
Stir in remaining ingredients and pour into preheated Dutch oven.
Bake for 50 to 60 minutes or until a wooden pick inserted in center comes out clean.
Cool for 10 minutes. Loosen bread by running a knife along the sides. Place a dish on top of the Dutch oven and turn upside down. The cake will now be on the plate.
Cool before slicing.