In a large pot add about 5 cups of water and a teaspoon of salt to the dried baby lima beans, bring to a boil, reduce heat, and simmer until the beans are tender, about 90 minutes. Add water to keep the beans covered if needed.

While the beans are cooking, make the pickled onion and celery so they can sit for awhile. Combine one chopped onion and the celery in a heatproof bowl and pour over enough boiling water to cover. Let them sit for about 5 minutes, then drain. Mix 2 tablespoons of honey and a teaspoon of salt with 1/2 cup of vinegar and add to the onion-celery mix. (If your beans are already cooked, let these sit for at least 15 minutes).

Heat a heavy skillet on medium heat to cook the other red onion with a pinch of salt in 3 tablespoons of olive oil. Cook, stirring occasionally, until the onion is deeply caramelized, at least 30 minutes. Add a little water if the onion looks like it’s burning but isn’t completely browned.

Roast the red bell pepper. If you have a gas range you can put the pepper directly on a lit burner and use tongs to turn it until the skin is mostly blackened. Or roast it whole in a 350°F oven until the skin is beginning to darken, about 30 minutes. Let cool, pull out the stem and seed core, and peel off as much of the outer skin as possible (it’s fine to leave some if it doesn’t come off easily). Chop into roughly 1/2 inch pieces. Save as much of the liquid from the pan as possible; a few seeds are okay, too.

Use a large bowl to combine the cooked lima beans, the caramelized onion (and any oil from cooking them), and the roasted red pepper, along with any of its cooking liquid. Drain and reserve about half of the vinegar-honey mix (save it for salads) from the pickled onion and celery, then add the vegetables. Add the chopped mint, mix well, taste, and add salt if needed. Serve at room temperature.