In a large bowl, combine the diced apples and sprinkle with sugar and lemon juice. Add the celery and grapes and toss to coat.
In a small pan, toast the pecan nuts for 2 minutes on low heat or until lightly browned.
Whip the whipping cream in another bowl until it peaks, then add the mayonnaise. Gently fold through the mixture with a spatula.
– Add the apple mixture to the dressing and season with salt and pepper. Let the salad chill in the fridge for at least 1 hour.