Preheat the oven to 450 degrees F.
In a 12 to 14-inch saute pan, heat 2 tablespoons olive oil over medium heat. Add the red onion and cook for 5 minutes, until soft and translucent. Add the red peppers, thyme, and oregano and saute over high heat for five more minutes, until the peppers and onions are very soft. Remove from heat, season with salt and pepper and set aside. In the same 12 to 14-inch saute pan, heat 2 tablespoons olive oil until smoking. Add the cavolo nero and the pepper flakes and cook until wilted and soft, about 4 to 5 minutes. Remove the pan from the heat, place the cabbage mixture into a bowl, stir in prosciutto pieces, and set aside.
Place the mushrooms on a sheet tray and drizzle with 2 tablespoons olive oil. Season with salt and pepper, place in oven and roast for 20 minutes. Remove from the oven and allow to cool. Chop the mushrooms into 1/4-inch cubes and place into a bowl with the juices that have exuded during cooking. Add the sage, season with salt and pepper, and set aside.
In a 12 to 14-inch saute pan, heat 2 tablespoons olive oil over medium heat until smoking. Add the leeks and cook, stirring occasionally, until the leeks are very soft and translucent, about 8 or 9 minutes. Remove from heat and allow to cool in a bowl. Tear the mint leaves by hand and add to leeks. Season with salt and pepper and set aside.
Drain the soaked beans and cook, covered with fresh water, over high heat until the beans are very tender but not waterlogged. Drain the beans, allow them to cool slightly, then mash with a potato masher or fork, taking care not to "whip" them too much. Stir in the minced garlic, rosemary, balsamic vinegar, and 1/4 cup olive oil. Season with salt and pepper, add more oil if necessary to create a smooth texture, and set aside.
Preheat the grill or broiler.
Grill or toast bread for 2 minutes, until browned and firm. Taste each of the mixtures for seasoning and moisten any that may be dry with a little extra-virgin olive oil and a squeeze of a lemon. Top each piece of toast with a heaping tablespoon of any of the mixtures and serve immediately.
Recipe copyright 2000, Mario Batali. All Rights Reserved.