Wash the trout, pat dry and cut diagonally on both sides. Chop the lovage and marjoram and stir with the butter, salt and pepper until smooth. Spread part of the butter mixture into the inclined slits (it is best to use your fingers) and the rest into the trout`s stomach cavity. Then wrap the trout in aluminum foil and grill for about 25 - 30 minutes, turning several times.
Anything you want goes as a side dish.
You can also put the trout on mushrooms, zucchini slices or pre-cooked potato slices, then wrap them in foil and grill them.