Silicone cake mould advice needed

[LaBelleSauvage123]

I’ve bought a silicone mould in the shape of a Christmas tree, similar to the one in the photo attached. Thought it would be good to bake a cake in it with the group of young adults with learning disabilities that I work with. But I have questions.

1. How do you ensure the cake doesn’t rise up so that when you invert it, it lies flat?
2. How do you decorate it without losing the details of the mould? Would it be best to slice it in half ( eek) and sandwich it with buttercream, leaving the top naked with perhaps just a dusting of icing sugar?

All ideas very welcome!

I don't know, but if practise with it first - I have up after I could never get the cake out of mind without it breaking up. I think you're meant to leave it to cool longer in silicone than you would in a tin.

Fill 3/4 of the way and once baked you can slice the bottom to be flat if it has risen too much. And yes cutting in half with buttercream is a good idea and you can decorate the top with royal icing and sifting icing sugar