Preheat oven to 350oF. Prepare baking pan and line with paper cups.
In the mixing bowl sift together flour, corn starch, baking powder and salt. Set aside.
In a large mixing bowl, beat together sugar and butter until light and fluffy.
Beat in the eggs one at the time, making sure each one fully incorporated.
Alternate adding the flour mixture and warm milk to the butter mixture. Scrape down the sides and mix again, making sure everything incorporated.
Using ice cream spoon, fill paper lined cupcake pan.
Bake at 350oF for 15-20 minutes. Cupcakes are ready when the toothpick, inserted in the center of the cupcake, come out clean and dry.
Transfer the cupcakes to a wire rack and leave them to cool down to room temperature.