Preheat the oven to 350 degrees F. Grease and flour two loaf pans and set aside. In a large bowl, whisk together the melted butter, oil and sugar until combined. Add the eggs and whisk again until creamy. Add vanilla extract and sour cream and whisk again. Add the grated zucchini and stir until combined.
Set a large sieve over the bowl and add the flour, cocoa powder, salt, baking powder, baking soda and cinnamon into it. Gently shake and tap the sieve until it is all sifted onto the wet ingredients. Gently fold and stir until the dry ingredients are completely incorporated into the wet ingredients.
Pour the mixture evenly into the greased and floured loaf pans. Spread gently, then sprinkle chocolate chips on top. Bake for 60 minutes or until a toothpick inserted into the centre comes out clean. Remove from the oven and cool in the pans before removing.
Preheat the oven to 350 degrees F. Grease and flour two loaf pans and set aside. In a large bowl, whisk the sugar and lemon zest together vigorously until fragrant. Add the melted butter and oil and whisk until combined. Add the eggs and whisk again until creamy. Add vanilla extract, lemon juice and sour cream and whisk again. Add the grated zucchini and stir until combined.
Set a large sieve over the bowl and add the flour, salt, baking powder and baking soda into it. Gently shake and tap the sieve until it is all sifted onto the wet ingredients. Gently fold and stir until the dry ingredients are completely incorporated into the wet ingredients.
Pour the mixture evenly into the greased and floured loaf pans. Spread gently. Bake for 45-50 minutes or until a toothpick inserted into the centre comes out clean. Remove from the oven and cool in the pans before removing. Once cool, make the glaze and drizzle over top of each loaf before serving.