Preheat the oven to 350 degrees F. Line a loaf pan with parchment paper and set aside. In a large bowl, whisk together the melted butter and sugar until combined. Add the egg and whisk again until creamy. Add the vanilla extract and sour cream and whisk again. Add the grated zucchini and stir with a spatula until combined.
In a small bowl whisk together the flour, cocoa powder, salt, baking powder, and baking soda. Add the dry ingredients and 1/2 cup of chocolate chips onto the wet ingredients. Gently fold and stir with a spatula until completely incorporated.
Pour the mixture evenly into the prepared loaf pan. Spread evenly, then sprinkle 1/4 cup of chocolate chips on top. Bake for 45 - 60 minutes or until a toothpick inserted into the centre comes out clean. Remove from the oven and cool in the pan for 10 minutes or so before removing the loaf using the parchment paper and transferring to a cooling rack.
Preheat the oven to 350 degrees F. Line a loaf pan with parchment paper and set aside. In a large bowl, whisk the sugar and lemon zest together vigorously until fragrant. Add the melted butter and whisk until combined. Add the egg and whisk again until creamy. Add the vanilla extract, lemon juice and sour cream and whisk again. Add the grated zucchini and stir with a spatula until combined.
In a small bowl whisk together the flour, salt, baking powder, and baking soda. Add the dry ingredients onto the wet ingredients. Gently fold and stir with a spatula until completely incorporated.
Pour the mixture evenly into the prepared loaf pan and spread evenly. Bake for 45 - 60 minutes or until a toothpick inserted into the centre comes out clean. Remove from the oven and cool in the pan for 10 minutes or so before removing the loaf using the parchment paper and transferring to a cooling rack.
Once the loaf is cool, mix the glaze in a small bowl and either drizzle it or spread it over the top of the loaf before serving.