My favorite vegetarian food hacks are Quinoa and Peanut Butter Oatmeal. Both are great sources of protein.

When I want to spend a weekend hacking, and don't want to be bothered, I'll cook a big batch of steel cut oats in the slow cooker, starting it on a Friday night. Then I know I can just mix in a few table spoon of the good "grind it yourself" peanut butter with a cup or two of oatmeal. It leaves me feeling satiated, and is rather healthy with lots of fiber and protein without much fat, and without sugar.