Birthday cake to take to a picnic

[ohwhattododo]

Looking for any ideas for a birthday cake I can make which will withstand transporting to a picnic at the zoo! Needs to hold up in the car (both to travel there and sit in the car 'til lunchtime) and potentially in warm weather as it's in July. For my daughter's birthday party, so would like it to be as special as possible.

I'd either do a vanilla traybake with icing and different sprinkles all over the top and decorate with candles and other things she likes, or brownies as they are much nicer when a bit warm and squidgy, decorated with candle etc

Isn't just nicer to just let people help themselves to whatever takes their fancy than decide what kind of cake fits the bill .

I did a giant cookie cake for a birthday in a heatwave. I didn’t use butter icing, but used royal icing instead. Something a little like this https://www.janespatisserie.com/2021/01/16/giant-birthday-cookie/

Maybe school cake? I bake mine in a rigid tray lined with parchment.
I think that would travel ok.

Equal quantities of butter, caster sugar, flour and eggs. Dash of vanilla and a pinch of salt.

Ice and cover in sprinkles when cool.

Link here: https://www.bbcgoodfood.com/recipes/school-days-sprinkle-sponge

A traybake cake sounds perfect, baked and transported in a foil tray. Either vanilla or chocolate school cake, loads of sprinkles, candles if you like. Knife and napkins to serve