Whisk all-purpose and cake flours, baking powder, cinnamon, and salt together in a large bowl.
1 ½ cups all-purpose flour, 1 cup cake flour, 1 tablespoon baking powder, 1 teaspoon ground cinnamon, 1 teaspoon kosher salt
Grate the frozen butter using a box grater.
¾ cup unsalted butter
Add it to the flour mixture and combine with a pastry cutter, two forks, or your fingers until the mixture comes together in pea-sized crumbs.
Place in the freezer as you mix the wet ingredients together.
Whisk 1 cup heavy cream, brown sugar, egg yolks, and vanilla extract together in a small bowl.
1 cup heavy cream, ½ cup dark brown sugar, 2 large egg yolks, room temperature, 1 ½ teaspoons vanilla extract
Drizzle over the flour mixture, add the cinnamon chips, then mix together until everything appears moistened.
1 ¼ cups cinnamon chips
Dump dough onto a lightly floured countertop.
Dip your hands in flour and work the dough into an 8-inch disc as best you can (does not have to be perfect).
Dough may be sticky. If it’s too sticky, add a little more flour. If it seems too dry, add 1-2 more tablespoons heavy cream.
Once in an 8-inch disc, cut into 8 evenly-sized wedges using a sharp knife or bench scraper.
Place scones on a parchment-lined baking sheet, 2-3 inches apart and refrigerate for at least 15 minutes.
Preheat oven to 400°F.
Remove scones from the refrigerator and brush tops with heavy cream then sprinkle with sparkling sugar.
sparkling sugar, 1 cup heavy cream
Bake for 22-25 minutes or until golden brown around the edges and lightly browned on top.
Remove from the oven and cool for a few minutes before drizzling with dulce de leche.
Warm the dulce de leche gently in a small saucepan over low heat or in a microwave-safe bowl on 50 % power for 30-45 seconds until it’s loosened up.
Using a whisk or the tines of a fork dipped in the dulce de leche, drizzle generously over warm scones.