Clean, wash and cut the leek into pieces. Wash and halve the tomatoes and cut out the stem. Peel and slice the banana. Wash fish, dab dry, sprinkle with lemon juice and salt a little.
Layer the prepared ingredients in a microwaveable, flat form. Mix sour cream, starch and eggs together. Season with salt, pepper and curry. Pour over the casserole. Cover with microwave foil and cook at 600 watts for seven to eight minutes.
In the meantime, roast the grated coconut in a dry pan until golden brown. Sprinkle over the casserole before serving. Garnish with lemon wedges and parsley.