Preheat oven to 350°F. Line 9x13-inch or 8x8-inch baking pan with foil, allowing for an overhang along the edges of the pan. Lightly coat foil with cooking spray. Set aside.
In a small bowl, beat together cream cheese and sugar until smooth. Add in flour, egg yolk, espresso powder, and vanilla. Mix until well incorporated.
In a large bowl, prepare fudge brownie mix according to package instructions. Fold chocolate chips into brown batter.
Spread about 2/3 of brownie batter into an even layer in prepared baking pan. Distribute dollops of cream cheese mixture on top. Follow with dollops of remaining brownie batter. Use a knife or mini offset spatula to swirl cream cheese mixture and brownie batter.
Bake for 25-30 minutes, until center of brownies is set and no longer jiggles. Cool brownies to room temperature in pan. Cover pan and chill brownies in the fridge until cold. Use the foil overhang to lift brownies out of the pan. Slice into desired portions. Keep chilled until ready to serve.