In a bowl, combine the flour, cornstarch, baking powder, baking soda and salt. Set aside.
In another bowl, whisk together the eggs and sugar for about 5 minutes or until they turn pale, form a ribbon, and triple in volume. Gradually whisk in the oil. With a spatula, add the dry ingredients alternately with the buttermilk until the mixture is just moistened (there will be some lumps of flour). Let stand for 10 minutes.
Preheat a waffle iron. Pour about 250 ml (1 cup) of batter at a time (for two waffles) and close the device (or as recommended by the manufacturer). Bake for about 5 minutes or until golden brown. Keep warm. Repeat with the remaining batter. Serve with strawberry sauce as a dip.
Variation You can gently fold frozen berries (raspberries, blueberries, etc..) into the batter, at the last moment, to prevent it from changing colour.