In a large saucepan, bring water to a boil and 2 tablespoons of salt.
Preheat oven to 450°F. Resting cauliflower on stem, cut from top to bottom 3 steaks of about 1 ½-inches in thickness, with stem attached. Reserve trimmed off florets for making cauliflower rice or roasted cauliflower. Add cauliflower steaks to boiling water and cook for 2 minutes.
Remove from water and pat dry. Place steaks in a baking pan and add 3 tablespoons of olive oil and salt and pepper to taste. Place in the oven and roast for 10-12 minutes until golden brown and stems are tender. Flip the cauliflower with a spatula halfway through the roasting process.
Meanwhile, prepare the vinaigrette by combining 3 tablespoons of olive oil, brown sugar, lemon juice, capers, raisins, almonds, and parsley. Add salt and pepper to taste.
Transfer cauliflower to a plate and spoon vinaigrette on top. Serve immediately.