Combine the first 4 ingredients in bowl. Spoon and pack this crust mixture into the bottom of a 10-inch spring-form cake pan. Place the pan in the freezer until the crust is set, about 20 minutes.
In the meantime, allow the vanilla or chocolate ice cream to soften at room temperature about 15 minutes. Scoop the ice cream into the cake pan. Use a thin spatula to evenly spread and pack the ice cream into the bottom of the pan. Put the cake back into the freezer until the ice cream is firm, about 20 minutes. While that occurs, allow the cherry or strawberry ice cream to soften at room temperature. Place the chopped chocolate and whipping cream in a small bowl and microwave in shorts spurts until chocolate is melted and evenly combined with the whipping cream. Take the cake out of the freezer and top the first layer of ice cream with the cherry or strawberry ice cream. Drizzle the top of the cake with the melted chocolate mixture. Place the cake back in the freezer for several hours or overnight, wrapping it once the chocolate has set.
To serve, run a hot water dampened paring knife around the outer edge of the pan. Unlock and remove the pan’s outer ring. Cut the cake into wedges and set on dessert plates. Garnish each serving with a whole cherry or strawberry. Serve immediately.