Caramelize the onions: Heat the oil in a 10 to 11-inch cast iron or other oven-safe skillet over medium heat. Add the onions and sauté for 2 minutes. Add 1 teaspoon of salt and the granulated sugar and stir. Turn the heat to medium-low and allow the onions to caramelize until they develop a tawny brown color and sweet fragrance, about 15 minutes. Keep an eye on the pan, stirring often. As the onions start to brown, slowly stir the onions continuously until they are done. Add a tablespoon of water, as needed, if the onions start to stick or brown too quickly.

Preheat the broiler on high. Place a rack about 6 inches away from the heat.

Create the sauce: Add the beef stock, Worcestershire sauce, and fresh thyme, and increase the heat to medium. Simmer and reduce the liquid by nearly half, about 4 minutes. Add the cannellini beans and pepper and stir to combine. Continue to cook for another 2 minutes to allow the flavors to come together. Taste, adding more salt if needed.

Broil: Meanwhile, combine the breadcrumbs and butter in a small mixing bowl and toss. Remove the sprigs of thyme from the pan. Top the pan of beans evenly with the cheese followed by the panko mixture, covering the entire surface. Pop the pan under the broiler and cook until the cheese is melted and the breadcrumbs are crisp, 2 to 3 minutes. Keep a careful watch so the topping doesn’t burn. Carefully remove from the oven and garnish with fresh parsley. Love the recipe? Leave us stars and a comment below!