1 medium onion, peeled, halved
2 cups soldier, cranberry, or pinto beans, soaked overnight, drained
1 cup any combination black barley, whole hull-less barley, rye berries, wheat berries, and/or other whole grains
4 cups coarsely torn whole wheat sourdough bread
¾ cup plus 2 tablespoons olive oil, divided
1 red chile, such as Fresno, sliced
2 tablespoons seasoned rice vinegar
1 head of garlic, peeled, separated into cloves, sliced
5 ounces maitake or other mushrooms, torn into bite-size pieces
1 small bunch of Tuscan kale, center ribs and stems removed, torn into large pieces
2 tablespoons red wine vinegar
Freshly ground black pepper
1 tablespoon (or more) fresh lemon juice
2 tablespoons sliced chives
Heat a medium skillet, preferably cast iron, over medium-high until very hot. Carefully lay a piece of foil inside skillet, followed by onion, cut sides down. Char onion until totally blackened on cut sides, about 15 minutes. Wipe out skillet and reserve.
Transfer onion to a small pot. Add beans and enough water to cover them by about 2". Give everything a stir and bring to a boil over medium-high heat, then reduce heat and simmer, skimming off any foam and adding water if needed to keep beans submerged, until beans are tender, 1½–2 hours. Season with salt. Ideally, they should cool overnight in their cooking liquid, but they’ll still be awesome if you can’t hit pause at this point. Meanwhile, cook grains in a large pot of boiling salted water until al dente, 50–70 minutes. Let cool in their liquid—ideally overnight, but same story as with the beans.
Preheat oven to 300°. Toss bread with ¼ cup oil on a large rimmed baking sheet. Season with salt. Squeeze and toss bread to absorb as much oil as possible. Bake until croutons are well-browned and very crisp, 35–45 minutes.
Meanwhile, combine chile and rice vinegar in a small bowl. Soak until ready to use.
Bring garlic and ½ cup oil to a simmer in a small saucepan over medium heat. Cook, lowering heat as needed to maintain a gentle simmer and swirling occasionally, until garlic is golden brown, 12–14 minutes. Using a slotted spoon, transfer garlic chips to paper towels. Reserve garlic oil.