In a medium bowl, combine the flour, cornstarch, baking powder, salt, nutmeg, cloves, and ginger. Set aside momentarily.
In a bowl fitted with a whisk attachment over medium speed, whisk together the melted butter, milk, and eggs until combined. Add the brown sugar and whisk until combined. Stop the mixer and fold in the rolled oats and cinnamon chips.
Sift the flour mixture over the butter/milk/oats/cinnamon chip mixture. Fold carefully until just combined. Be careful not to over mix, or the batter will be tough.
Pour half the batter over the prepared loaf pan. Breaking the cinnamon filling into small pieces, add it to the entire surface of the batter. Add the remaining batter, and then sprinkle with the crumb topping.
Bake the muffins for 40-45 minutes, or until the topping is a light golden brown and a toothpick inserted into the middle of the cake comes out clean. Remove from the oven and allow to cool for about 5 minutes. Remove cake from, inverting it onto a rack and allow to cool completely.