Season the fish fillet all around with salt, season with pepper and rub with olive oil.
Place on a plate brushed with olive oil. Sprinkle with finely chopped spring onions and grated orange zest or zest cut with a zester (see tip).
Place on a saucer – e.g. an upturned cup or a wire rack – in a saucepan in which water is boiling three fingers high. Put on a generously high lid and gently cook the fish fillet in the rising steam for about six to eight minutes. Next to the kitchen stove for another five minutes before serving. Apropos the wok is ideally suited for steaming! For the sauce, cut the orange with its peel into pieces, remove the seeds and remove. Blend the orange pieces with the remaining ingredients in a hand mixer and beat until creamy. Gently heat this sauce in the microwave or serve it with the fish just as cooled. If you want to serve it warm, you can also add the juice from steaming the fish.
A fresh baguette will suffice as an accompaniment, and a dry Chardonnay is recommended as a beverage to counter the strong citrus aromas. Especially if it has been aged in barrique, or small oak barrels. We drank a Chardonnay from the Kaiserstuhl with it.