Step 1

Preheat your oven to 350° degrees F. Line a 9x13 light metal rectangular baking pan with foil or parchment, extending the foil or parchment paper over the edges of the pan. Spray the foil lightly with cooking spray; set aside.

Step 2

For the cookie bars: In the bowl of a stand mixer, cream together the softened butter, brown sugar and granulated sugar with the paddle attachment until creamy and smooth, about 1 minute. Add in the egg and egg yolk, mixing well, followed by the vanilla, scraping down the bottom and sides of the bowl as needed. Lastly, add in the baking soda, cornstarch, ground cinnamon, salt, and flour until a soft dough comes together. Spread the dough evenly into the prepared pan.

Step 3

Bake the bars for about 25-30 minutes or until light golden brown and a toothpick inserted near the center comes out clean or with moist, but not wet, crumbs. Cool completely.

Step 4

For the caramel layer: In a medium saucepan, combine the sweetened condensed milk, butter, brown sugar and corn syrup together over medium heat. Cook, stirring occasionally, so butter melts and mixture becomes well combined. As mixture comes to a boil, begin to stir it constantly. Once the mixture comes to a full boil, reduce the heat to medium-low and simmer the caramel mixture, stirring constantly, for about 10-15 minutes or until thickened and golden brown. The mixture should almost pull away from the sides of the pan. Everyone's stovetop is different, so your mixture may thicken and brown sooner than 10-15 minutes, or take longer. Just keep your eye on it. Remove from the heat and whisk in the vanilla and salt.

Step 5

Pour the caramel layer evenly over the cooled cookie bars. Spread into an even layer. Cool completely at room temperature, uncovered, about 2 hours, or you can expedite the process by cooling it in the fridge for about 1 hour.

Step 6

For the white chocolate layer: In a small bowl, whisk together the granulated sugar and cinnamon. Set aside for now. Meanwhile, add the white chocolate chips to a medium bowl. Pour the heavy cream into a microwaveable glass measuring cup and microwave until hot to the touch, about 30 seconds. Pour the hot heavy cream over the white chocolate chips in the bowl. Let the mixture stand for about 3-5 minutes, then slowly whisk the mixture until fully smooth and melted.

Step 7

Pour the white chocolate ganache layer evenly over the cooled caramel layer and smooth it out into an even layer. Immediately top with the cinnamon sugar mixture and lay it on thick. Allow the white chocolate layer to harden and set, about 1 hour at room temperature, before cutting into squares to serve. You can also expedite this layer by refrigerating for about 30 minutes. For the cleanest cuts, I like to run a very sharp knife under super hot water, wipe the blade dry, and cut, repeating this process after each cut. A clean, sharp and HOT knife makes for super clean cuts.