1. Peel and thinly slice potatoes in the round. Wash, drain and then pat dry.
2. Meanwhile, place half of the butter in ovenproof skillet and place in 400° preheated oven until butter melts. Remove from oven and layer potatoes, onions, salt, pepper, and parsley in skillet. Top with remaining butter and the Italian dressing.
3. Return to oven and bake until potatoes are tender and lightly browned.