Preheat oven to 425F. Line a loaf pan with parchment paper. Shred zucchini(about 2 medium) and ring it in handfuls over the sink to drain water until you get 2 cups, set aside.
In a mixing bowl add 1 2/3c. AP flour, 1c. sugar, 1 tsp. baking powder, 1 tsp. baking soda, 1 tsp salt, 1 tsp. cinnamon, 1 tsp allspice and mix. Add shredded zucchini to the dry mix and toss with your hands until evenly coated.
In a small mixing bowl add 1/2 cup sourdough discard, 2 large eggs, 1/3 cup applesauce, 1/3 cup sour cream (or greek yogurt), mix well.
Add wet ingredients to the dry, fold together with a spatula careful to not overmix.
Pour batter into prepared pan and bake for 10 min. Lower the temp. to 350F and bake another 50-55 min. Let cool