In a stand mixer fitted with the paddle attachment or a hand mixer, beat the softened cream cheese until smooth. Scrape down the bowl once complete.
Add sugar, sour cream, vanilla extract, flour and salt. Beat on medium until smooth. Do not over beat. Scrape down the bowl once complete.
Add in eggs, one at a time, beating on low after each addition until just combined. Do not over beat.
Remove the dulce de leche from the can and place in a medium-sized bowl. Heat it in the microwave for 20-30 seconds, or until the consistency matches that of the cheesecake batter. Stir well.
Add ½-¾ cup of cheesecake batter to the softened dulce de leche. Mix until combined.
Pour the remaining cheesecake batter over the brownie bottom and spread evenly.
Evenly spoon the dulce de leche mixture over the cheesecake batter (evenly space 12-16 spoonfuls, or until you have used all of the mixture).
Use a fork or the end of a spoon/fork to swirl the batter together.
Bake for 40-45 minutes or until the center has just a slight jiggle. Remove from oven and let cool to room temperature.
Cover and chill in the refrigerator for 6 hours - overnight before serving.