Roast the cumin and coriander sees in a dry frying pan until fragrant and them grind with a mortar and pestle or spice grinder. This is know as 'dhana-jeeru' and is used frequently in Indian cooking. ( there will be leftover, save of next time :))
Melt the butter with the oil in a large pan and add the onion, cloves, cinnamon stick and peppercorns. Cook, stirring occasionally, over a medium high heat until the onion is softened.
Discard the cinnamon stick, Add 1 tbsp of the dhana-jeeru mix, the garam masala, and the turmeric and fry for about 30 seconds, stirring.
Add the can of tomatoes, garlic, ginger, salt and tabasco.
Cook the mixture over medium heat for about 5 minutes.
Add the ground lamb and break up and mix into the mixture. Cover and cook over a low simmer for 35 minutes, adding the peas 10 minutes before the end.
Serve over rice.