Make the spicy costing, combine puree, oil, vinegar, ketchup, mustard, onion, sugar, garlic, chilli powder and salt and pepper in a food processor, blend until smooth.
Make 3 deep cuts in each drumstick, arrange in a single layer in a shallow dish, and spoon the spicy costing over them. Sprinkle with half of the sesame seeds.
Bake in a pre-heated oven 190oC/375oF/Gas Mark 5 for 30 minutes, basted throughout the cook. Turn half way through the cook and sprinkle with remaining sesame seeds. Serve hot or cold.