I am hoping to make one for DD2's 1st birthday party this weekend. I make traditional cakes (square/round/oval, etc.) for weddings and Christenings etc but have never attempted a fondant covered shaped cake. Any ideas or tips? I was going to use this as a rough idea but with fondant instead of buttercream.
Never done a toadstool, but have done a pig which uses cakes cooked in two pyrex bowls like the link.
You can get a pretty good idea of how much mixture you need by filling your bowls with water to a bit over 2/3 and seeing which of your normal tins it fills to the same level (A bit of a pain given my usual tin is loose bottomed but it does work)
And you'll probably find the cakes are a bit slow cooking, Pyrex is not as quick as tins.
Otherwise I'd say its easier than a formal cake because it doesn't have to be immaculate, just colourful with lots of sweets - small children never eat the cake.