Simmer raspberries, sugar, and vanilla over medium heat for 5 to 8 minutes until thickened.
Strain raspberry sauce to remove seeds and set aside.
Beat cream cheese and sugar until smooth, then add egg and vanilla and mix until creamy.
Whisk flour, cocoa powder, and salt in a bowl.
In a separate bowl, mix oil, sugar, and vanilla, then add eggs one at a time.
Combine the dry ingredients with the wet ingredients just until blended.
Spread brownie batter evenly in the prepared baking pan.
Pour the cheesecake mixture over the brownie batter, then spoon raspberry sauce and swirl gently with a skewer.
Bake at 350°F for 30 to 35 minutes.
Cool completely, then chill the brownies for 2 hours.
Cut into heart shapes using a cookie cutter and serve.