Traditionally the baker not only carried out the fundamental work of baking the bread, but also made available his ovens at the end of his own baking. People would bring their prepared dishes to him to be cooked in the cooling ovens. I did this when I lived in Greece, making up large dishes of moussaka and the like, taking them to the baker. They were eaten warm that day and then cold in following days. Like m,ost people, all I had in the house was a single gas burner.