Preheat the oven to 375 degrees F.
Combine the cauliflower, prosciutto, dates, olive oil, salt and red pepper flakes in a large mixing bowl. Mix well to coat and place onto a sheet pan. Place in the top half of the oven and roast until the cauliflower is fork tender and light brown, about 30 to 40 minutes. Remove from oven, transfer to a decorative bowl and serve warm with the caper aioli on the side.
Rub the inside of a decorative bowl with the garlic clove.
Put the mayonnaise, salt, olive oil, capers, caper brine and parsley in a mixing bowl and mix well to combine. Transfer to the decorative bowl and serve with roasted cauliflower.