Bring a large pot of water to a boil for the pasta.
Toast the walnuts in the oven or in a pan over moderate heat. Chop and reserve.
Heat a large skillet over medium-high heat with olive oil, 2 turns of the pan. Add bacon and render 2-3 minutes; add leeks and garlic, and season with salt and pepper. Stir 2-3 minutes more then add white wine. Wilt in chard then reduce heat to low.
Salt boiling water liberally and cook pasta to al dente. Reserve 1 cup of starchy, salty water before draining pasta.
Drain pasta then add half the starchy water to the pan along with the pasta and half of the nuts. Toss pasta in sauce and adjust salt and pepper to taste. Add more water if dry then toss with grated cheese and a fat drizzle of good olive oil; top with more nuts and cheese.
Cooking is more about interpretation than creating something new. When chefs write a recipe its often a cover song—an interpretation of a classic recipe, a manipulation of a basic sauce or a new approach to an already proven set of techniques. Once in a while you come up with a recipe that surprises you, a dish that begs you to pat yourself on the back. This dish may become our new family favorite, taking down carbonara. It’s our new classic!