• Preheat oven to 350°. Line a 9- by 13-inch cake pan with foil, leaving some foil hanging over all four sides. Lightly grease the foil.

To make the first layer

• Whisk together flour, baking powder, and salt in a small bowl, set aside.
• In a bowl of stand mixer fitted with the paddle attachment or with a hand mixer, beat the butter and the sugar until light and fluffy, 3 to 5 minutes.
• Add the egg and the milk and beat in, scraping down the sides of the bowl.
• Stir in the dry ingredients, until completely combined.
• Evenly place spoonfuls of the mixture into the prepared pan and spread it into an even layer with an offset spatula. (save the mixing bowl for the next step- don't wash)

To make the second layer

• In a small bowl, whisk together the corn syrup (or golden syrup) with the milk (or cream), and vanilla.
• In the bowl of your mixer, beat the butter with the sugar, and salt until light and fluffy.
• Beat in the egg, scraping down the sides of the bowl as needed
• Beat in about a third of the 1 1/4 cup flour, then beat in half of the milk/corn syrup mixture. Beat in another third of the flour, then the remainder of the milk/corn syrup mixture. Then stir in the last of the flour.
• Dollop spoonfuls of this batter over the first layer and spread evenly with offset spatula.

For the topping and to bake

• Mix together the sugar and cinnamon, then sprinkle it evenly over the cake.
• Bake the cake for 25 minutes until cake is gently set in the center, it may still be slightly "wet" in the center. Remove from oven and let cool on a wire rack. The center of the cake will settle as it cools- this is normal.
• Once cooled, lift out the cake using the the foil, and cut the cake into squares.