01 -
Preheat the oven to 350 degrees F. Grease two standard loaf pans, then dust lightly with flour and tap out the excess.
02 -
In a medium bowl, whisk the flour, cinnamon, allspice, baking soda, baking powder, cream of tartar, and salt until evenly combined.
03 -
In a large bowl, whisk the oil, eggs, sugar, and vanilla until smooth and slightly glossy.
04 -
Add the dry ingredients to the wet ingredients and stir just until combined. Fold in the grated zucchini until evenly distributed. The batter will be thick but spreadable.
05 -
Stir together the topping sugar and cinnamon. Divide half of the batter between the pans, sprinkle with half of the cinnamon sugar, then repeat with the remaining batter and topping.
06 -
Bake for 45-55 minutes, until the tops are golden and a toothpick inserted in the center comes out clean or with a few moist crumbs.
07 -
Cool in the pans for 15 minutes. Run a thin knife around the edges, turn out onto a rack, and cool at least 45 minutes more before slicing.