For the roasted cauliflower: Preheat oven to 425 degrees. In a large mixing bowl add cauliflower florets, peppers, and shallots. In a separate bowl, make the sauce. Whisk together the tahini, harissa, honey, lemon juice, salt, and hot water until smooth. Pour the sauce over the cauliflower mixture and toss until fully coated. Arrange in an even layer on a sheet pan and bake for 20-25 min or until lightly charred and tender.