Finely grind juniper berries and pepper in a mortar.
Finely grate the lemon juice, grate the tarragon and chop the dill. Mix everything with oil and juice of one lemon.
Rinse fillets in cold water, dry and divide into portions. Rub with the seasoning oil and cover and refrigerate for one night.
Grill the fillets first on the skin side for 4 minutes, then flip and grill for another 4 minutes.
Arrange the trout fillets and serve.