Bring 100 ml of water to the boil, sprinkle in amaranth, bring to the boil while stirring and allow to swell for about 35 minutes at low heat in a closed pot, stirring several times. Wash the peppers, cut them in half lengthwise, cut one half into small cubes. Wash apple, quarter it, remove core, cut quarter into small cubes. Stir apple and paprika cubes into the amaranth and season with salt.
Put half of the paprika on top. Steam together for about 10 minutes. Heat the grill pan, put a few drops of oil on some kitchen paper, rub the grill ribs with it. Rinse fish fillet, dab dry, rub with salt and pepper, place on the hot grill pan, grill on both sides for about 3 minutes
Peel the ginger and chop very finely. Bring to the boil with mustard, vinegar, sugar and 3 tablespoons of water, season to taste with salt. Put the paprika half on a plate. Rinse off the mint, put some aside for garnishing, chop the remaining leaves. Season the amaranth vegetables with salt, pepper and chopped mint, fill into the pepper half. Arrange the fish with the mustard sauce, garnish with the remaining mint