Poached Whitefish on the Grill

3 lbs. Whitefish Fillets
1 tsp. Pepper
3 T Butter
1 Small onion, minced
2 tsp. Salt
4 T Water
4 T Lemon Juice
1 T Parsley

Rub fillets with salt and pepper, frizzle with lemon juice, then with butter. Sprinkle on onion and parsley. Add water, wrap in foil and place over medium barbecue coals for 20 minutes, Turn occasionally.