Roasted Cauliflower without seasoning prosciutto

1 medium head of cauliflower (about 1 1/4 pounds), cored, cut into 1-inch florets 6 tablespoons olive oil, divided 2 medium onions (about 1/2 pound each),[...]

1 (1 1/4 lb) cauliflower , cored, cut into 1-inch florets 6 tablespoons olive oil , divided 2 (1/2 lb) onion , halved lengthwise, cut into 3/4-inch-wide[...]

1 (1 1/4 lb) cauliflower , cored, cut into 1-inch florets 6 tablespoons olive oil , divided 2 (1/2 lb) onion , halved lengthwise, cut into 3/4-inch-wide[...]