1-First, preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

2-In a large bowl, cream together 1/2 cup unsalted butter, 1/3 cup granulated sugar, and 2 tablespoons brown sugar until light and fluffy.

3-Beat in 1 large egg yolk and 2 teaspoons vanilla extract, then stir in 2/3 cup sweetened condensed milk for extra richness.

4-In another bowl, whisk together 2 cups all-purpose flour, 1 tablespoon cornstarch, 1 teaspoon baking powder, 1/2 teaspoon baking soda, 1/4 teaspoon cream of tartar, 1/4 teaspoon salt, and 1/2 teaspoon cinnamon powder.

5-Gradually add the dry ingredients to the wet mixture to form the dough, incorporating the dulce de leche for that signature swirl.

6-Scoop the dough onto the baking sheet, and for a fun twist, roll in cinnamon sugar made from 3 tablespoons granulated sugar and 1/2 teaspoon cinnamon powder.

7-Bake for 10-12 minutes until golden, then let cool before topping with cream cheese frosting prepared from 2 sticks unsalted butter, 1/4 cup cream cheese, 2/3 cup sweetened condensed milk, 2 tablespoons dulce de leche, and 2 teaspoons vanilla extract.