Preheat your oven to 350°F (175°C) and line a square baking pan (approximately 8x8 inches) with parchment paper.

Melt 1 cup of unsalted butter over low heat, then stir in granulated and brown sugar until creamy. Cool slightly, then whisk in eggs and 1 teaspoon of vanilla.

Sift in 1 cup of cocoa powder and 1 cup of flour, folding gently until just combined.

In a separate bowl, beat 8 ounces of cream cheese with 1/4 cup of sugar, an egg yolk, and 1/2 teaspoon of vanilla until smooth.

For the sauce, cook 1 cup of raspberries with 1/4 cup of sugar and lemon juice over medium heat for 5-7 minutes, then strain if desired.

Pour the brownie batter into the pan, dollop the cream cheese and raspberry sauce over the top, and swirl with a skewer.

Bake for 25-30 minutes. Check doneness with a toothpick; it should come out with a few moist crumbs.

Cool completely in the pan, lift out using parchment, then slice into squares.