Preheat oven to 350 ° and spread a little butter in a 9 x 5-inch loaf pan.
In a large bowl, combine the flour, sugar, baking powder, salt, cinnamon, and nutmeg.
Add the coconut, toasted walnuts, and cinnamon.
In a medium bowl, whisk together the eggs, oil, sour cream, vanilla, and lemon zest. Add the grated carrot to the egg mixture, then mix with the dry mixture until just combined.
Spread the batter into the prepared loaf pan. Bake until a toothpick inserted in the center comes out clean. Let cool 30 minutes before serving.