Microgreens are fun and don't take much effort. I recommend trying out mung beans, alfalfa sprouts, and radish sprouts, many different kinds of "fancy" mushrooms can be grown for pretty low effort and you will end up with pounds upon pounds of them. Both of these can be easily grown indoors during winter months (assuming you have that where you live, and you're going into them).

Out of doors, peas and squash, and depending on time scale we're talking about fruit trees maybe? The nice thing about squash is they store for months and who doesn't like squash?

Dandelions are very edible and take zero effort to grow. You can make the roots into a tea that tastes kinda sorta like coffee. It's better than coffee I've had at some gas stations at least. The greens are a little bitter, but if you pick the big ones early in the year they can be really tasty. In spring I often make a saag aloo-ish dish with dandelion greens instead of spinach. If you uproot the whole thing then hold it by the root you can shake out the blades of grass. That's the easiest method I've found.