If your fish is really pristine, consider slicing it thinly and serving it raw.
4mackerel fillets (about 130gm each)For brushing:olive oil4thick large slices rye or miche bread½garlic clove, peeled, for rubbingTo serve:mayonnaiseTo serve:extra-virgin olive oilQuick kohlrabi pickles1(350gm) kohlrabi, peeled and shaved on a mandolin60 ml(1/4 cup) Champagne vinegar1golden shallot, thinly sliced½ cuptorn flat-leaf parsley¼ cuptorn dill2 tspcaster sugar1 tspsea salt flakes
For kohlrabi pickles, combine ingredients in a bowl, toss and set aside while grilling the fish.
Preheat a char-grill pan over high heat, brush mackerel with oil and grill until golden and just cooked through (1-2 minutes each side). Set aside on a warm plate.
Brush bread with oil, grill until charred, rub with garlic, then transfer to plates, top with grilled fish, kohlrabi pickles and a dollop of mayonnaise, season with black pepper and extra-virgin olive oil and serve.