I made an ice cream cake for my son's birthday and used this technique of spreading the ice cream in a foil lined pan & letting it harden. It worked GREAT!! I have 3 identical 13x9 cake pans, so I used 1 for the ice cream layer, and then made 1 cake mix that I distributed between the other 2 pans & shortened the baking time (instead of doing 1 cake and then slicing it in half).
Is there any benefit of freezing the ice cream separate still if doing a round shape and using a cake ring or springform pan? I have done this a few times and used a springform to bake the cake, removed it, used same pan to bake a choc chip cookie layer, cooled, then on top of cookie, added softened icecream, cake layer, then froze, then when firm, frosted with buttercream and decorations (whipped topping is easier but person I make them for specifically likes the buttercream with icecream cakes). I then just remove the ring from the springform and transfer cake to cakeboard. The issue is that its super hard to cut, even after letting it soften for 10 mins at room temp first and then using a hot knife. Its the cookie layer that is the prob, it just gets too hard when frozen. Thats another issue though. My question was though, can anyone see an issue with letting the icecream freeze on the cake as opposed to doing it separate when using springform?