Lay the mackerel fillets onto a tray and sprinkle with salt. Splash 2 tablespoons of the vinegar over them and leave for 6 minutes
Finely shred the cabbage and mix with the chopped dill. Add the remaining 2 tablespoons of vinegar and the olive oil. Season with salt and mix well
Slice the gooseberries in half
To serve, pop the slaw onto the plate. Add the fish then a good dollop of crème fraîche. Place the gooseberries over the top then finish with the nasturtium leaves