Heat the pot over the gas stove or campfire, then add the oil, spam, and onions. Cook until the spam is browned, stirring regularly.
Add the can of cream of celery soup to the pot along with a can’s worth of water. Use this water to wash out the last of the soup that may be stuck to the can.
Heat until the soup just starts to boil then stir in the rice. Heat while stirring until hot and starting to simmer. Don’t be tempted to add salt until you have tasted it first as the spam can be quite salty. Serve straight away.