Get a 13 x 9 inch baking pan. Spray with cooking spray, line with parchment paper (or wax paper), and spray again with cooking spray.
Heat oven to 350 degrees.
Place 2 sticks of butter and unsweetened chocolate in microwave safe bowl. Nuke for 15 second intervals, stirring in between, until everything is melted.
In a separate bowl, mix together 3 cups sugar and 6 eggs, 2 tsp vanilla and 1 tsp salt. Beat until smooth.
Add flour a little at a time, beating between each addition. Add in chocolate mini morsels.
Pour chocolate batter into prepared pan.
In a clean bowl add cream cheese, 1/4 cup sugar, 1/2 tsp vanilla, and 1 egg. Beat till very smooth!
Spoon dollops of cream cheese mixture on top of chocolate mixture. Take a knife and carefully marble the cream through the chocolate.
Bake for 30-35 minutes or until set. Don't not over-bake. It just has to stop jiggling in the center.
Allow to cool completely before cutting.
Store in the fridge inside an air-tight container! They'll never last this long, but they should be good for about 2 weeks.