Cut capsicums in half and remove pith and seeds. Then, cut into large pieces.
Peel the onions, cut in half and slice thinly.
Remove the shells of the prawns, keeping the heads intact.
Put items from steps 1-3 into a casserole dish, and sprinkle with soy sauce and a pinch of salt.
Place on a wire rack and cook at 'Combi 3' (220°C + 440W) for 5 minutes. After that cook at 'Convection' 220°C for 20 minutes.
In a pot, add the soup stock (dashi), soy sauce and mirin (sweet sake). After it comes to a boil, add corn starch which has been pre-dissolved in water to thicken.
Remove the casserole from step 5 from the microwave oven, pour on thickened sauce from step 6, and heat on 'Microwave Power' at 'High' for 3 minutes.
Finally, add olive oil and dried parsley as a finishing touch.