Craft Your Raspberry Swirl: In a small saucepan, gently simmer the raspberries, 1 tablespoon sugar, and 1 teaspoon vanilla for 5-8 minutes until the sauce thickens slightly. For a silky-smooth finish, press it through a sieve to remove any seeds. Set aside to cool.
Whip Up the Cheesecake Topping: With an electric mixer, beat the room-temperature cream cheese with 1/3 cup sugar until wonderfully smooth. Stir in the egg and 1/2 teaspoon vanilla just until everything is combined and creamy – avoid overmixing!
Prepare the Fudgy Brownie Batter: In one bowl, whisk together the flour, cocoa powder, and salt. In a separate, larger bowl, combine the oil, 1 1/2 cups sugar, and 1 tablespoon vanilla. Beat in the eggs one at a time until the mixture is glossy. Now, gently fold the dry ingredients into the wet mixture, stirring only until no streaks of flour remain – this keeps your brownies perfectly fudgy!
Assemble and Swirl Your Masterpiece: Pour the brownie batter evenly into your parchment-lined 8x8 inch baking pan. Carefully spoon the creamy cheesecake mixture over the brownie layer. Next, add small dollops of your prepared raspberry sauce on top of the cheesecake. Take a knife or skewer and gently swirl through the layers to create beautiful marbled patterns.
Bake, Chill, and Shape Your Hearts: Bake your brownies in a preheated oven at 350°F (175°C) for 30-35 minutes. The center should have a slight jiggle. Let them cool completely on a wire rack, then transfer the pan to the refrigerator for at least 2 hours (or until firm). Once chilled, use a heart-shaped cookie cutter to create your adorable Valentine's brownies!