Cooking for one is often treated as a problem to solve, with special recipes and special portions. I have stopped treating it that way.
My rule is simple: one pan, one bowl, and enough left over for tomorrow’s lunch. Rice, greens, an egg, a little sauce. It takes twenty minutes, it tastes good, and there is not much to wash up.
The trick is not a recipe, it is a habit. Once cooking for one feels normal instead of sad, it becomes one of the pleasanter parts of the day.