Hi MacMadame,
Research hemp hearts, the inner part of hemp seeds. They are so healthy, have lots of calories and all your essential fats, protein, and so much more, besides they taste wonderful.
I have been sprinkling these on my oatmeal now for a year or more, but can be eaten with a spoon all by themselves.
I get these from Alberta here in Canada but I am sure you will find some closer to your home.
I will incorporate them back into my diet when I am able after sleeving, as I like them that much!