Preheat your oven to 350°F (175°C). Prepare a 9x13-inch baking dish by greasing or lining with parchment paper.

In a large mixing bowl, combine ½ cup of melted butter with 1 cup of brown sugar. Stir until well mixed, then incorporate 2 large eggs and 1 teaspoon of vanilla extract, blending until smooth and creamy. Gently fold in 1 ½ cups of all-purpose flour and a pinch of salt.

In a separate bowl, mix ½ cup of brown sugar with 1 tablespoon of ground cinnamon and 2 tablespoons of melted butter until it resembles wet sand to prepare the cinnamon swirl.

Spread the blondie batter evenly into the prepared baking dish. Dollop spoonfuls of the cinnamon swirl mixture on top and use a butter knife to swirl them together lightly.

Bake in the preheated oven for 25 to 30 minutes until the edges are golden brown and a toothpick inserted into the center comes out mostly clean.

While the blondies cool, beat 4 ounces of softened cream cheese until smooth. Gradually add 1 cup of powdered sugar and 2 tablespoons of milk, mixing until creamy.

Once cooled, drizzle the cream cheese icing generously over the top. Allow the icing to set before cutting into squares.