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

In a large mixing bowl, blend together 1 cup of granulated sugar, ½ cup of brown sugar, and ½ cup of melted unsalted butter until smooth.

Add in 2 large eggs and 1 teaspoon of vanilla extract, mixing until fully incorporated.

Sift 1 cup of all-purpose flour, ½ cup of cocoa powder, and ½ teaspoon of salt into the bowl, gently folding the dry ingredients into the wet mixture without overmixing.

In a separate bowl, beat together 8 oz of softened cream cheese, ¼ cup of sugar, 1 egg yolk, and 1 teaspoon of vanilla extract until creamy.

In a saucepan, combine ½ cup of raspberries, ¼ cup of lemon juice, and ¼ cup of sugar over medium heat, stirring until the mixture becomes saucy.

If desired, thicken the raspberry sauce by mixing 1 tablespoon of cornstarch with 2 tablespoons of water and adding it to the sauce, cooking until glossy.

Pour half of the brownie batter into the prepared pan, dollop the cream cheese mixture and spoon the raspberry sauce over it, swirling to create a marbled effect.

Cover with remaining brownie batter and use a skewer to swirl for a marbled look.

Bake for 25-30 minutes or until the top is set and a toothpick comes out with a few moist crumbs.

Let the brownies cool completely in the pan for at least one hour before lifting them out and cutting into 16 squares.