Much the same as for more than one - only I know I do not need to have anything I do not really like.
I live by myself, but see no reason not to eat well and healthily because of that, so a normal day would mean brekkie in the morning, (porridge with extra blueberries and large mug of tea,
Lunch is usually something with eggs, (I do adore eggs in most forms, but specially soft boiled/poached) so likely to have toast with some baked beans and poached eggs - using toaster and microwave, this meal would take me something under four minutes to make - also large mug of tea.
Evening meal - I use my electric steamer so have four or five different (from the freezer) veg, with potatoes and usually a ;piece of fish cooked in the halogen oven, or else a salad with either rice or pasta and fish. Glass of water to drink.
Cooking for one is the same as cooking for two or three. When I do have company for the evening meal, I usually cook enough for us all plus extra that I can freeze as individual portions for when I feel like something different