A Nissan Thermos wide mouth and a pool noodle
1. Preheat thermos.
2. Heat the meal or food to the boiling point, in a pot on your stove top, and then once your food is boiling hot, you pour the food into your preheated thermos bottle, and finish cooking the food in the thermos.
3.When you have added your food, and covered it tightly with its lid, then lay your thermos on its side, as all the food will cook more evenly that way. (If you leave it standing upright sometimes only the food on the bottom will cook.) For this method, you still need to pre-heat your thermos. Don’t forget to preheat it as it is very important.
What can I cook?
Oatmeal , whole wheat breakfast cereal , pasta , rice, or rice and beans, or rice and lentils or rice and chopped up veggies .
There are instructions for some dishes here. thermos cooking has a nice general overview and The Boat Galley has recipes and solid practical advise (eg. don’t cook with cheese, its impossible to remove from the thermos) .