Preheat your oven to 350°F (175°C) and prepare an 8x8 inch baking pan with parchment paper.

Melt 1 cup of unsalted butter in a mixing bowl. Add 1 cup of light brown sugar and 1 cup of granulated white sugar, mixing until smooth. Beat in 2 large eggs until well combined.

Sift in 2 cups of all-purpose flour, 1 teaspoon of baking powder, and 1 tablespoon of cinnamon. Fold the mixture gently until just combined.

Pour half of the blondie batter into the prepared pan, layer with cinnamon sugar, dollop remaining batter, and swirl with a knife.

Bake for 30 to 38 minutes until edges are golden brown, and center is slightly underdone. A toothpick should come out with a few moist crumbs.

Remove from oven and cool for about 15 minutes. Lift blondies from the pan using parchment paper and let cool completely on a wire rack.

Prepare frosting by mixing 2 cups of powdered sugar with softened cream cheese and a splash of milk until smooth.

Once cooled, drizzle frosting over blondies, allow to set, then slice into squares and serve.