In the days after I came home from hospital, the first solid food I tried was quiche. I could eat a good sized portion as the texture is soft and easy to digest. Quiches contain eggs, cheese and milk combined so are packed full of nutrients and are calorific.
Most supermarkets offer crustless varieties so you won’t get too full up on pastry. Higgidy is a good range as they offer slightly different flavours beyond the usual Quiche Lorraine and Cheese and Onion and they even make frittatas which have no pastry at all.
In the early weeks I would eat half a small quiche with nothing else but then I started to eat a third or a quarter plus some vegetables or blob of hummus.
I am planning to start to make my own so I can put in extra veg and nutrients.