Split pea and lentil soup. Get dried green split peas and dried red lentils. Put them in a pot, pour in water, add stock or salt and some dried parsley and thyme, bring to a boil then simmer for 1~1.5 hours.
Cheap, filling, healthy, and a lot of filler ingredients work in it if you want to change it up. I’m recovering from a crushed ankle, on a crutch so I’ve had to figure out one handed recipes to a degree.
Another good one if you have a rice cooker - coconut milk, lime juice, peanut butter and some sugar. Melt it all together, have it on rice. Again, something that’s adaptable for adding other ingredients.