First, let's turn the oven on to 180°C (350°F), and If your oven has a fan setting, you should bake the cake at a slightly lower temperature of 160°C (320°F), as the fan will cook the cakes faster! Give your two 8-inch cake pans a nice coating of grease.
In a bowl, gently sift together your flour, cornstarch, baking powder, baking soda, salt, ginger, cinnamon, cloves, and nutmeg. Use a whisk to mix them until they look perfectly combined, and then set those dry things aside for a moment.
In a large bowl, bring together the light brown sugar, vegetable oil, blackstrap molasses, egg, and vanilla. Whisk these lovely wet ingredients until they are smooth and well combined.
Now, add the dry ingredients to the wet mixture. Use your whisk to mix them until they are just combined. Don't worry, the batter will be very thick at this stage!
To finish, pour in the hot milk. Give the batter one last whisk until it is smooth and lovely—be careful not to overmix!
Divide the batter evenly into your two prepared pans. Gently drop the cake tins a little onto the counter to release any large air bubbles. Bake them for 28 to 30 minutes, or until a toothpick poked into the middle comes out clean or with just a few moist crumbs clinging to it.
Let the cakes cool in their pans for 20 minutes, then turn them out onto a wire rack to cool completely. While they are cooling, we can start on that wonderful frosting!