Grease your spingform pan well, bake brownies in pan according to directions. Let cool for a couple hours, when cool cut top 1/2 layer off (this will be the middle layer of your cake) Don't worry too much if it crumbles a little, I found that after I cut through the brownie I put a large plate on top and fliped it upside down to seperate the layers w/o it breaking apart.
Spoon SOFTENED Ice cream on top of the brownie layer. (I kept the ice cream in the fridge for a couple hours and it was perfect) I topped this layer with carmel...
***NOTE*** Carmel does not freeze (OK maybe you all know that, but I didn't.) Don't use too much or you will end up with carmel oozing out the side of your cake! I also sugest freezing the icecream layer for a bit first, because my carmel kinda sank into the ice cream.
Freeze this layer for a couple hours or till firm.
Then add another layer of brownie, carmel and ice cream. Again freeze for several hours or overnight.
You could easily make several different variances using different ice creams, candy, cookies, or even fruit!