Trying a new baking tool

I got a couple of rolls of plastic cake collars a few weeks back. I was going to get a pre-sized metal one, but this idea sounded better because I could custom size it to my cakes (and it’s reusable, too).

Today I made a lemon sponge cake with layers of cream and lemon curd topped with candied lemon slices (they were too bitter). It turned out beautifully. Unfortunately, once it was cut it had a massive cream-alanche. I need to use more stable insides (like a mousse) next time.