@sheromon I've done a few pies carefully in the BlueBike basket with a towel underneath for padding. Once I did a tart that was peaches over pastry cream across Cambridge. Again on a BlueBike, choosing the least bumpy route and going pretty casually.

At some point I want to get better options to mount to my bike, but until then BlueBike is pretty good. I think either way I'd stay away from cake, bouncing is just going to compress it and ruin it. I usually make cookies partially due to their robustness on a bike.