Fusilli with Cavolo Nero, Roast Shallots and Walnuts

1) Slice the shallots about 1cm thick. If using onions, cut them in half lengthwise, and then slice into half-moon shapes of the same thickness. Toss these in a roasting pan with two tablespoons of olive oil, the balsamic vinegar, and salt and pepper to taste. Roast at 200 degrees Celsius for thirty to thirty-five minutes, stirring occasionally, until tender and ever-so-slightly charred at the edges.
2) While the onions are roasting, cook the pasta in just barely enough water to keep it covered as it boils - add more if the pasta starts to rise from the depths - for about fifteen minutes. It should be al dente. Drain almost all of the water, leaving the pan slightly damp, and add the cavolo nero along with the remaining olive oil. Cook over medium heat until the cavolo nero starts to wilt; about three to five minutes, then stir in the roasted onions.
3) Serve topped with walnut halves or chopped walnuts (toasted if desired).
Source of recipe: Heavily modified from the back of a bag of cavolo nero.