Begin by peeling and washing the 3-pound potatoes.
Cut into 1/2-inch slices, and place in a bowl.
Peel, wash, and slice the white onion; set aside.
Set the oven to 400 F.
Boil potatoes in salted water briefly.
Remove, and drain.
Heat oil in an oven-proof pan.
Sauté onions with salt and white pepper, then garlic.
Transfer onion mix to bowl.
Melt butter in a pan.
Layer potatoes, onions, repeat.
Oven-cook 13-15 minutes until golden.
Remove, gently lift potatoes with a spatula.
Slice into 10 pieces, garnish with parsley.