Preheat the oven to 350 degrees Spray a 9x9 inch baking dish with non-stick baking spray.
In a large bowl, whisk together the melted butter, cocoa powder and sugar until combined. Whisk in the egg and vanilla extract until combined. Stir in the flour and salt until it is just combined in the batter. Fold in the chocolate and cherries.
Spread the brownie batter in the greased baking dish.
cherry cheesecake swirl
In the bowl of your electric mixer (or with a hand mixer), beat the cream cheese until smooth and cream. Beat in the sugar, egg yolk, vanilla and cherries until smooth and combined.
Drop spoonfuls of the cheesecake batter all over the brownie batter. Use a knife to swirl the cheesecake mixture into the batter.
Bake the brownies for 35 to 45 minutes, until they are set in the center and the cheesecake part is golden. Let cool completely before slicing and serving.