In a medium bowl, sift together all-purpose flour, cornstarch, baking powder, baking soda, salt, cinnamon, ginger, cloves, and nutmeg. Using a whisk, mix until well combined and set aside.
In a large bowl, combine light brown sugar, eggs, vegetable oil, milk, vanilla, and grated apple. Whisk until smooth and well combined.
Add the presifted dry ingredients to the wet ingredients and gently fold together using a spatula until just combined. Be careful not to overmix. Stop mixing as soon as there are no large streaks of flour remaining and the batter is uniform.
Pour the batter into the prepared loaf tin and spread it out into an even layer. Tap it on the counter once to remove any large air bubbles.
Remove the streusel from the fridge. If it has clumped together, use your fingers to gently break it up into smaller pieces. Evenly scatter all of the streusel over the top of the batter. It may seem like a lot, but make sure to use it all for the best flavour!
Bake for 65–70 minutes, or until a toothpick inserted into the centre comes out clean or with a few moist crumbs attached. If you notice the top browning too quickly, loosely cover it with a piece of foil after about 55 minutes.
Allow the bread to cool in the tin for about 20 minutes. Carefully run a thin knife along the edges without parchment paper, then use the parchment overhang to lift it out. Transfer to a wire rack and allow to cool completely before slicing and enjoying!