Combine granulated sugar, cocoa powder and salt in a large bowl. Add melted butter and vanilla. Mix into dry ingredients until well combined. Stir in eggs, one at a time. Once batter looks shiny and thick, add flour and mix it in well. Keep stirring until ingredients have been incorporated. Fold the chocolate chips into the batter. Spoon about a tablespoon of the brownie batter into each of the wells of prepared muffin tin(s).
In a separate bowl, beat the cheesecake swirl ingredients (softened cream cheese, granulated sugar, vanilla extract and egg yolk) together until fully combined. Add a dollop of the cheesecake swirl batter (about 1/2 Tablespoon) to the top of each brownie cup. Take a knife and gently swirl the cheesecake batter down into the brownie batter.
Bake at 350 degrees for 15-20 minutes (until toothpick comes out clean). Check them at 15 minutes. Keep an eye on them so you don't overcook them! When done, remove them to a wire rack to cool. Let brownie bites COOL before trying to remove them from the pan. Repeat process with remaining batter (if making them one muffin tin at a time)...then ENJOY!!!!!
***These brownie bites also freeze very well, if by some miracle there are any left... just sayin'!
Chocolate Chip Cheesecake-Swirl Brownie Bites https://www.thegratefulgirlcooks.com/chocolate-chip-brownie-bites/