Quarter capsicums, remove seeds and membranes. Grill capsicums, skin side up, until skin blisters and blackens. Peel away skin; chop flesh roughly.
Heat oil in pan, add onion, garlic and spices, cook, stirring, over medium heat for about 5 minutes or until onions are very soft and translucent. Add tomato, cook 5 minutes or until tomato is very soft.
Blend or process capsicums until smooth, add tomato mixture and nuts, blend until combined. Cover, refrigerate several hours or overnight.