Preheat oven to 400°F. Arrange the broccoli and cauliflower on a baking sheet and drizzle with 2 tablespoons oil. Place the garlic head in a small piece of aluminum foil and drizzle with remaining oil. Fold to seal. Place on baking sheet with veggies. Sprinkle the veggies with rosemary salt (or regular salt.) Bake for 30 minutes.