Preheat oven to 350°F. Place a wire rack over a baking sheet and set aside.

To make the waffles, in a large bowl, whisk together the flour, cornstarch, sugar, baking powder and salt until evenly combined. In a separate bowl, whisk together the buttermilk, egg yolks, oil and vanilla. Pour mixture into the dry ingredients and whisk until just combined, and no flour streaks remain.

In a separate clean bowl, beat the egg whites until stiff peaks form. Gently fold in the beaten egg whites into the batter, being careful not to over-mix. Set aside while you preheat your waffle iron. Once hot, grease with cooking spray and spoon about 1/3 cup batter into each cavity. Cook according to your waffle iron's directions. Place the cooked waffles on the prepared baking sheet, in a single layer, and continue making the rest until the batter is all used up.

Once all the waffles are done, place them in the oven to re-crisp and warm up.

To make the chocolate sauce, in a small saucepan, combine the chocolate, butter, cinnamon, sugar, and cream. Set over moderate heat and cook, stirring often, until melted through and smooth. Keep warm on the stove over very low flame.

When ready to assemble the churros, place the melted butter in a shallow dish and combine the sugar and cinnamon for the topping in a separate shallow dish. Cut the waffles into logs and dip each waffle piece into the melted butter and then into the cinnamon sugar mixture. Continue until all the churros are coated. Serve with the warm chocolate sauce. Enjoy!