Petits pois, for example. Fresh peas are not available year-round. People buy them in cans or jars, already cooked and sometimes seasoned. Peas and carrots. Peas and mushrooms. I bought a six-pack of canned peas a few weeks ago because they were a well-known brand on sale at a good price and we can have them all winter, cooked with either fresh carrots or fresh mushrooms, which are available year-round.
It helps if the peas are treated nicely by the companies that process and pack them. For example, the peas I bought don't contain any chemical additives, just salt and sugar. And the instructions on the can say that they should be drained before being cooked and served (à égoutter avant utilisation). Rinsing them is a good idea too, to remove extra salt and sugar used in the canning process. Then you can put in fresh water or your own broth when you cook them. With some butter too, of course, and a lettuce leaf or two.
A few years ago, I was talking with a British friend — the woman who left Bertie the black cat with us when she moved back to England seven years ago — and she tossed off a comment about French food that I remember. "The peas you get in France are very good," she said. "Even the ones in tins are delicious." I had always thought the same thing. An Englishwoman should know. When I was growing up in North Carolina, we called green garden peas "English" peas, to distinguish them from our local "field" peas like black-eyed peas.