Preheat oven to 350°F (175°C) and grease a 9-inch springform pan with butter or non-stick spray.
In a large bowl, combine melted butter and granulated sugar. Whisk in eggs and vanilla extract until well incorporated.
Sift in cocoa powder, flour, and salt. Fold the dry ingredients into the wet mixture until no streaks remain.
Pour the brownie batter into the prepared springform pan. Bake for 25 to 30 minutes. Remove from oven and allow to cool completely in the pan.
Spread the softened vanilla ice cream in an even layer over the cooled brownie base. Cover with plastic wrap and freeze for 2 hours.
Spread the softened chocolate ice cream over the vanilla layer. Smooth the top with a spatula. Return to the freezer for 4 hours or until firm.
Prepare the ganache by heating heavy cream in a small saucepan until simmering. Pour over chocolate chips in a heat-proof bowl and let sit for 5 minutes, then whisk until smooth.
Pour the chocolate ganache over the frozen chocolate ice cream layer. Freeze for an additional 30 minutes before releasing the springform sides and serving.