Preheat oven to 425°F (232°C). Line a baking sheet with parchment paper.

In a large bowl, whisk together flour, cornstarch, sugar, baking powder, baking soda and salt.

Add in pieces of the cold butter and with your hands or pastry blender cut the butter into the dry ingredients until mixture resembles wet sand. Make a well by forming the dry ingredients into a mound and creating a hole in the centre.

In a small bowl or measuring cup, whisk together the milk and egg until well combined. Pour the mixture into the well of the dry ingredients. With a rubber spatula, quickly combine mixture until it just comes together. Do not over mix!!!

Lightly dust work surface with flour and then transfer the dough onto the floured work surface. Fold the dough over on itself a couple of times and then gently pat together and flatten it out to 1 1/2 inches thick all around. With a round cookie cutter or water glass, cut out as many rounds as possible. Gently pat together the scraps, roll, and cut out the remaining rounds.

Place scones about an inch and a half apart on the prepared baking sheet.

With a pastry brush, lightly brush tops with a dab of heavy cream.

Place into the preheated oven and bake for 12 to 15 minutes or until tops are golden and the scones have risen. Cool slightly on pan and carefully remove onto a wire cooling rack to cool completely. Enjoy immediately