Preparation:

1. Preheat the Cuisinart toaster Oven Broiler to 350? F. Arrange the walnuts in a single layer on a baking sheet. Toast the walnuts until golden and fragrant, about 5 to 7 minutes. Remove the walnuts from the oven and allow to cool completely.
2. Place the grapes in the work bowl of the Cuisinart Food Processor fitted with the metal chopping blade and pulse 10 times to chop. Add the lemon juice and balsamic vinegar and process until smooth, about 30 seconds. As the processor is running, add the oils to emulsify, about 30 seconds. Season the dressing with salt and pepper.
3. Place the lettuces, grapefruit slices and avocado pieces in a large bowl. Drizzle with half the dressing and toss to combine. Drizzle the remaining dressing and garnish with the toasted walnuts. Serve immediately.