Preheat oven to 375 degrees F. Toss cauliflower with 2 tablespoons olive oil and 3/4 teaspoon salt. Roast for 35 minutes, stirring once.
Meanwhile, mince the garlic and set into a bowl, then pour lemon juice on top. Let sit while cauliflower roasts. This helps make the garlic “linger” in your mouth less.
When cauliflower is done roasting, add to a food processor or high speed blender. Add 2 tablespoons olive oil, remaining salt, garlic and lemon juice, tahini, and water. Blend until completely smooth, adding a little more water if needed.
Spoon onto a plate and make a small well in the middle, drizzle with remaining 1 tablespoon olive oil. Garnish with olives and fresh parsley. Serve with crackers.