Vegetarian Cassoulet with Mushrooms and Chard

In a large cast iron or oven-proof skillet (a shallow Dutch oven will also work), heat the oil. Sauté the leeks, celery and carrot over medium-high heat until soft and beginning to brown, about 10 minutes. Add garlic and mushrooms; continue cooking until mushrooms have released their moisture and browned, about 5 minutes. Fold in chard and sauté until wilted, 2 minutes.

Season vegetables with sea salt and pour in the wine, scraping up any brown bits that may have formed on the bottom of the pan. Stir in the beans to incorporate. Pour the broth over the bean mixture and arrange the thyme sprigs on top. Bring to a simmer and cook, uncovered, over medium heat until the beans are soft and the liquid is mostly absorbed, 10 minutes. With the back of your spoon or a potato masher, smash a quarter of the beans to thicken the sauce.

Preheat the broiler. Sprinkle the cassoulet with the breadcrumbs and broil until golden brown. Serve warm alongside crusty bread or cauliflower mash.