Preheat oven to 350 degrees. Line an 8×8 baking pan with foil so that there is enough to pull the brownies out once they are done. Butter or spray lightly with baking spray. Set aside.
Over a double broiler, melt butter, sugar and chocolate. Whisk until smooth. Let mixture cool on counter for 5 minutes. Pour into the bowl of a stand mixer. Add vanilla and one egg, mix, then add the other egg, mix until incorporated.
In a small mixing bowl whisk together flour, cocoa powder and salt. With mixing speed on low, gradually add the dry ingredients. Mix until just combined. Remove bowl from stand and fold in chocolate chips. Set aside.
For the cheesecake batter, in a medium size mixing bowl, combine cream cheese, sugar, salt and vanilla. Beat until smooth. Add egg yolks one at a time, then mix until just combined. Set aside.
For the eggless cookie dough, in a small mixing bowl, combine butter, brown sugar, flour, salt, vanilla, and water. Mix until combined, then gently fold in the mini chocolate chips. Roll into ½” balls. Set aside.
To assemble, pour the brownie batter into the prepared pan. Pour the cheesecake batter on top and carefully spread to create an even layer. Submerge cookie dough balls into the cheesecake. Place in oven and bake for 35-40 minutes or until the cheesecake is set and is slightly golden brown around the edges.
Remove from oven and let cool in pan for 30 minutes before chilling in the refrigerator for 1-2 hours. When ready to serve, remove from pan using the foil overhang. Peel foil from brownies, cut and serve.