Preparation Heat oil in heavy large skillet over medium-low heat. Add bacon; sauté until almost crisp, about 6 minutes. Add walnuts; sauté 1 minute. Add greens and toss until wilted but still bright green, 5 to 7 minutes. Season to taste with salt and pepper. Transfer to bowl. Sprinkle with cheese, if desired, and serve.
Preparation Heat oil in heavy large skillet over medium-low heat. Add bacon; sauté until almost crisp, about 6 minutes. Add walnuts; sauté 1 minute. Add greens and toss until wilted but still bright green, 5 to 7 minutes. Season to taste with salt and pepper. Transfer to bowl. Sprinkle with cheese, if desired, and serve.