Preheat oven to 200° F.. Spread the nuts on a baking sheet and bake until lightly toasted, 6-7 minutes. Coarsely chop and set aside. (*Cheaper to buy nut pieces, roast; easier too.)
Peel, quarter and core the apples. Cut into ½–inch dice. Place in a bowl and toss with lemon juice. Add the celery, bell pepper,green onions and nuts. Stir to combine.
In another bowl, combine the sour cream, mustard, honey and mint. Whisk together until well blended, and season with salt and pepper.
Separate the lettuce leaves and use only the crisp inner leaves; reserve the large outer leaves for another use. Arrange lettuce leaves around the rim of a serving plate.Add the dressing to the apple mixture and mix well. Spoon salad into the center of the plate.