Makes 4 servings Ingredients 4 small sweet potatoes, scrubbed 3 tablespoons extra-virgin olive oil, divided use Kosher salt, to taste 2 tablespoons unsalted butter 3 medium yellow onions, thinly sliced Freshly ground black pepper, to taste 1 lb 8 oz mixed mushrooms, like oyster, shiitake, or cremini, cut into bite-sized […]