Step 1 Preheat oven to 200°C. Mix curry paste with 2 tablespoons of the yoghurt in a glass or ceramic dish. Add lamb slices to dish and turn to coat. Cover dish and leave lamb to marinate for 10 minutes.
Step 2 Meanwhile, set a large non-stick frying pan over medium–high heat and spray with olive oil. Drain lamb slices of excess marinade, add to pan and cook for 1–2 minutes per side, or until browned. Remove lamb from pan and set aside.
Step 3 Place butternut pumpkin in a medium microwave-safe bowl with 1 tablespoon water. Cover bowl and microwave on high for 3 minutes, or until tender; drain.
Step 4 Spread cauliflower crusts with an even layer of tomato paste. Top crusts with reserved lamb slices, pumpkin, tomatoes and onion, then scatter with cheese.
Step 5 Place pizzas in oven and cook for 10 minutes, or until cheese is bubbling and golden.
Step 6 Cut pizzas into slices, drizzle with remaining yoghurt, garnish with coriander and serve.