1. Preheat oven to 425°F. In a large bowl, combine 2 tbsp. of the oil, ½ tsp. salt, and 2tbsp. harissa; mix well. Add cauliflower and toss to evenly coat. Spread on a rimmed baking sheet and bake for 35 minutes, tossing once halfway through, until tender. Remove from oven and toss with remaining 2 tbsp. harissa; bake for another 5 to 10 minutes, until caramelized and charred in some spots.
2. Meanwhile, prepare tahini honey by combining the remaining 2 tbsp. oil, ¼ tsp. salt, tahini, honey, lemon juice, and black pepper; stir with a whisk. Whisk in 1tbsp. water to thin out to the desired consistency.
3. Transfer baked cauliflower to a bowl or serving platter. Drizzle with tahini honey, and garnish with fresh parsley, if desired.
