Finely slice the fennel and place in a bowl. Wash the apple then coarsely grate, leaving the skin on, then grate the celeriac. Mix everything together, along with the crème fraiche, lemon juice and mustard. Set to one side in the fridge for an hour or 2. Then when ready to serve, stir in the parsley and rocket and season with pepper.
Pre heat the grill. Brush the skin of the trout with a little olive oil, season then place skin side up on a baking tray. Place under the grill and cook for 4 minutes until the skin is crispy. Then turn the fish and cook for a further 2 minutes on the flesh side.
Serve the trout with your Kanzi® apple remoulade.