Preheat oven to 200°C/180°C. Lightly grease and line base and sides of a 20 x 30cm rectangular slice pan.
Place sweet potato on a lined oven tray. Spray with oil and bake for 15-20 minutes until tender.
Beat eggs, cream and half of the cheese together. Layer sweet potato and broccoli over base of pan. Pour over egg mixture. Sprinkle with basil and remaining cheese.
Meanwhile, make the dipping sauce by combining yoghurt, garlic, lime juice, coriander, salt, pepper and Sriracha into a small bowl.
Bake for 25-30 minutes until golden and set. Stand for 5 minutes before slicing.