Roll the trout in a little flour. Heat 75 grams butter in a frying pan over medium-low heat without browning. Lay the trout in the pan, and season with salt. Squeeze the juice from one of the lemon wedges over the fish. Cook the fish for about 20 minutes, carefully turning half way through.
Just before serving, heat the last 50 grams of butter in a small saucepan along with the parsley. Arrange the fish on a serving platter and pour the parsley butter over the fish.
Arrange the finished fish on a serving platter. Fillet it at the table. Divide the sauce over the two servings and accompany each with a couple of lemon wedges.