Preheat oven to 350 degrees. Spread walnuts on baking sheet in a single layer. Bake 5-7 minutes until lightly toasted. In a food processor, combine the cranberries, vinegar, onion, sugar and mustard. Pureé until smooth. Gradually add oil and season with salt and pepper. In a salad bowl, toss together the greens, apples and enough of the cranberry mixture to coat. Sprinkle with walnuts and blue cheese. Contributed by: