For the cake you can get silicone teddy bear moulds on ebay for a couple of pounds. It makes about 13 tiny ~3cm teddy bears - I have used these to make tiny coloured cakes, then put them into a larger cake tin and put cake mixture around it and bake. Key thing seems to be to use same recipe for both batches so they don't float to top/ bottom. Google twice baked cakes or polka dot cakes. Then decorate as you would any cake - mini teddy bear picnic sounds great and the guests will oh and ah just like a rainbow cake.
I don't have much to say other than I did a teddy bear's picnic cake years ago when I did a lot of sugar craft and it was super easy especially if you do a square cake as you say. I made the bears from marzipan as its almost exactly the right colour. You can use dusting colour in darker brown to add shading etc too.
Oooo you guys are FAST! Thank you! Have a few cookie cutters and cake toppers highlighted on ebay and some rosettes that I thought we could give to all of the bears. Any ideas on the cake? Could do a square one with a picnic rug and bears on it, or try to do a bear shape... Last year did a rainbow cake so feel I have to live up to that one really!
I have decided on this as she loves the book and the song and I think this is probably a good age to do it. I am unsure on the following: 1. Should I do this at home or find a wood? More true to life/book v.s ease 2. Thinking about decorating to a woodland theme; toadstools and trees, lots of picnic rugs..any other ideas? 3. Food should be relatively OK as a picnic is after all a picnic, but would like to have a few 'bear-y' type things. 4. Party games - yay or nay? To be honest none of the are great at sharing expert at mugging though so not sure if this is really needed. 5. Craft station - thinking about getting paints or sequins out to decorate a pre-cut bear shape. I have 5 spare bibs, but not sure if this is a good idea thinking of parents not wanting kids to get messy?
Any other ideas welcome - I haven't really thought about the cake yet!