In a small bowl, combine the mayo, hot sauce and lemon juice. Stir until combined and set aside. In another little bowl, combine the herbs de provence, paprika, garlic powder and cayenne. Toss over the shrimp, coating them. Heat the oil in a medium frying pan. Add the coated prawns and sear on one side for 2 minutes. Flip and sear a further minute. Remove from heat.Spread the mayo along the inside of the brioche.