Cut swordfish into a large bite-size pieces.

Cut carrot randomly using the rangiri method into bite-size pieces. Blanch them for a few minutes until they are almost cooked through, then drain.

Cut the capsicum vertically into about 3cm wide strips, then cut each strip diagonally into bite-size pieces.

Halve the onion vertically if it is a whole onion, then halve horizontally. Cut each quarter vertically into 2.5cm wide pieces.

Trim off the base of the mushroom cluster, leaving the cluster still intact. Separate the cluster into small bunches of a few stems. (note 2)

Put all the Sweet and Sour ingredients, excluding corn flour/cornstarch diluted in water, in a jar or a bowl. Mix well until lump free.

Put the fish pieces and corn flour/cornstarch (not the one diluted in water) in a bowl and dust the swordfish pieces thoroughly (note 3).

Heat 1½ tablespoons of oil in a deep-frying pan over medium heat.

Place the swordfish pieces in the pan and cook for about 1.5-2 minutes until the surface is slightly browned. Turn them over and cook further 1.5-2 minutes until they are almost cooked through (note 4).

Rotate the fish pieces to quickly cook the sides of each piece where possible. This will make sure that the corn flour/cornstarch on the side of the fish pieces is cooked.

Transfer the fish to a plate.

Wipe the frying pan with kitchen paper and add the remaining oil to the pan. Heat over medium high heat.

Put all the vegetables in the pan and stir-fry for about 3 minutes until the surface of the vegetable pieces start browning.

Add the swordfish pieces to the pan and gently mix.

Pour the Sweet and Sour Sauce into the pan, gently stir for about 20 seconds.

Pour the corn flour/cornstarch with water to the pan, drawing a ring to spread it evenly. Quickly, but gently, mix it into the sauce. When the sauce is thickened and there is no white patch of corn flour/cornstarch (note 5), remove the pan from the heat.

Serve immediately.