With our morning coffee before we walk, we always have a biscuit. This week, we had these, which I had made the day before (from a Pilsbury dough type container):
They are at their best fresh. To warm them the next day for our walk, I heated a small back pad, wrapped them in foil and put them on top of the back pack, inside a small insulated bag. They were warmed through and springy by the time we had our coffee!