Prepare brownie mix according to package directions. Before baking, stir in 1 cup chocolate chips. When brownies are done, remove from oven and spread pecans, toffee and remaining 1 1/2 cups chocolate chips on tops. As chocolate melts, gently mix the topping together. Let brownies cool. Mix eggs, condensed milk, sugar, cream, half-and-half, salt and vanilla together. Refrigerate mix for several hours or overnight. In a small saucepan, mix 2 cups of the milk mix with the cocoa and heat through. In the top of a double boiler, melt the unsweetened chocolate. Very slowly stir in the heated cocoa and milk mixture until well mixed. Add to remaining milk mixture and refrigerate. Chop brownies into small pieces (1/4-inch) and put in the freezer. Put milk mixture in ice cream freezer and begin freezing. After 10 minutes add frozen brownie pieces and finish freezing.