Heat a little oil in a pan and gently fry the onion, garlic and spices. When the onion has softened add the lamb mince and continue to cook. When the lamb has browned add the tomato paste and 1 cup of water.
Process biscuit in a food processor until fine crumbs. With the motor running add the melted butter. Press mixture into a lined 24cm loose bottomed cake tin. Refridgerate for 30 minutes.