Put onion & garlic in a large heatproof non-metalic bowl with stock cube and half pint boiling water. Stir well, then cover and microwave for 3 minutes.

stir in rice with another half pint of boiling water, cover and microwave on high for 10 minutes, stirring after 5.

Stir the fish into the rice with the peas and another half pint of boiling water. Cover and microwave on high for 4 minutes. Check the rice is cooked - if not, cook for another minute. Leave to stand for 1-2 minutes for the liquid to be absorbed. Stir in the butter and season well. Serve hot.