Preheat oven to 325°F. Slice top ½ inch from each head of garlic. Place each, cut side up, on large square of foil. Sprinkle with salt and pepper; drizzle with oil. Enclose each in foil. Roast packets directly on oven rack until garlic is tender, about 1 hour 10 minutes. Carefully open foil; cool.
PREPARE THE DRESSING:
Squeeze roasted garlic into a medium bowl; mash. Whisk in remaining dressing ingredients.
ASSEMBLE THE SALAD:
Combine vegetables in a large bowl. Add dressing, a little at a time (you may not wish to use it all); toss. Season with more salt and pepper, as desired.
Notes
If you are preparing this recipe as GLUTEN-FREE, just be sure to use a brand of mayonnaise that is known to be GF.
The dressing may be made up to one day ahead, just cover and chill.
If you are counting WW Points or just want to cut back on calories, be sure to use low fat mayo and buttermilk.
Cut this recipe in half if you don't have to feed 10 people.