Preheat oven to 350°F.
In a medium mixing bowl, whisk together the dry ingredients except the cornstarch.
In another medium mixing bowl, whisk the wet ingredients and the cornstarch.
Whisk the dry ingredients into the wet ingredients, whisking only until the ingredients are incorporated. Do not over whisk the filling.
Spray a muffin pan with non-stick spray, or use only Baker’s Joy baking spray.
Pour the filling into the prepared pan, filling each ⅔ full.
Bake for 25 minutes.
Remove from the oven and let the cupcakes sit in the pan for 20 minutes.
Remove each cupcake from the pan and place in the refrigerator for 1 hour.