This plant-based power meal fills the centers of broiled bell peppers with an Italian-inspired white bean-and-chard mixture; the result is a quick and nutritious weeknight dinner or even a make-ahead lunch to enjoy the next day.
Roughly chop leaves of Swiss chard and thinly slice stems. In a large skillet, heat oil over medium-high. Add garlic and chard stems; season with salt and pepper. Cook, stirring, until fragrant, 1 minute.
Add 1/4 cup water to skillet; cover and cook until stems are tender, 5 minutes. Uncover and stir in chard leaves, white beans, Parmigiano-Reggiano, and vinegar. Remove from heat.
Preheat broiler, with rack 6 inches from heating element. Place peppers on a baking sheet, drizzle with oil, and season. Broil peppers, cut-sides down, until tender and charred in places, 10 to 12 minutes.
Remove from oven and stuff, cut-sides up, with bean mixture. Sprinkle 3/4 cup grated fontina over tops. Broil until cheese is melted, 1 to 2 minutes; serve.