Ingredients: Potatoes, onion, butter, cream, flour, Parmesan, pepper, salt.
Options: ham, garlic.
Method: Cast-iron skillet; medium hot (350ºF) oven for over an hour.
Pre-heat oven (and pan, while you are collecting your ingredients). Butter bottom of skillet. Slice onion, cover bottom. Slice potatoes (mandoline if you have one), layer. Sprinkle with flour, parmesan, salt, pepper, pour cream (follow your heart). Layer potatoes. Dot with butter. Sprinkle, pour. Layer onions, layer potatoes, sprinkle leftover chopped onion bits (the parts that don’t slice cleanly), sprinkle flour & Parmesan, salt & pepper, pour cream. BAKE!! Medium hot oven for one hour, 15 minutes. Test for doneness by poking.
Pull it from the oven and *LET SIT FOR HALF AN HOUR*.