Cook the rice according to the packet instructions but add the stock cube to the water for flavour.
Chop the onion and garlic.
Heat oil in a pan over medium heat and gently cook the onion until it starts to soften. Add the garlic and cook for a further minute.
When the rice is cooked, thoroughly drain it and add it, along with the smoked pepper mackerel fillets (torn into small pieces) and the chopped broccoli and cauliflower.