When it comes to birthday cakes, kids usually prefer simple flavours but lots of icing - and then just eat the icing. Our daughter requested a vanilla PJ Masks cake for her 5th birthday, so this is my first foray into fondant icing. It was easier than I thought. I just drew and cut out a template of Owlette's mask onto paper, then rolled out the store-bought red fondant, placed the template on top and cut it out. The black parts are cut from a licorice log. The white eyes are made from a mixture of egg white and icing sugar mixed to a pliable dough, rolled out and the shapes cut out, then chilled in the fridge.
I searched for a sponge recipe that didn't involve creaming and it worked fine.

225g self-raising flour (I used spelt and added a little bit more baking powder)
2 tsp baking powder
225g soft butter
220g caster sugar (I ground up organic golden sugar in a coffee grinder)
4 eggs
1 tsp vanilla extract
2 tsp milk

Filling: 1/2-3/4 c strawberry jam, sieved
Buttercream icing:
250g soft butter
500g icing sugar
1/2 tsp vanilla extract
1 tbs milk

Preheat oven to 160C. Line 2 x 20cm sponge tins.
Sift the flour and baking powder in a large bowl or in a food mixer. Add the rest of the ingredients and slowly beat (by machine or hand-held electric mixer) until combined. You can also add a few drops of food colouring if you want a coloured sponge (I made a pink cake). Divide mixture into half and spoon into each cake tin, level out.
Bake 25-30 min or until a poked-in skewer comes out clean. The cakes will be slightly browned and have come away from the edge of the tin.
Leave to cool in the tins for 10 minutes before removing and cooling completely on a wire rack.
Make the buttercream icing by cutting up the butter into cubes and beating with an electric mixer until soft. Slowly beat in the icing sugar 1 tbs at a time. Add the vanilla extract. If the icing is too stiff, add enough milk so the icing is easily spreadable.
Level out your two sponges with a knife if they are lopsided or too raised in the middle.
Place the bottom sponge on your serving plate or board, secured in place with little dabs of icing underneath. Put pieces of baking paper around the edges of your cake. Spread icing onto the bottom sponge, followed by the jam. Place the other sponge on top. Cover the top and sides of the cake with the rest of the buttercream icing, and level out with an offset palette knife. Then place your fondant pieces on top. Remove the baking paper pieces.
You can see bits of crumb in my icing but you can avoid that by doing a crumb coat first. Use about 1 1/2 c of buttercream to ice all over the cake and sides (don't worry if there's see-through) then use a bench scraper to smooth out the sides if desired. Put in the fridge for about 20 min to harden. Then ice the cake again with buttercream, smooth out and set in the fridge.