You can also use a pot cosy. These were (re)invented by an African woman whose name escapes me. It’s basically a fabric donut or bucket, packed with insulation (wool felt, sometimes polyester). They heat the pot of food to a boil, then take it off the heat and stick it in the pot cosy. It stays hot for 4 times longer than a naked pot, saves a ton of energy, or in the case of the inventor, a shit load of fuel. Historically, villagers would stick the pot in a pile of hay or wool to get the same insulating effect.