Ingredients:
Soften the onions in a splash of oil with a pinch of salt until caramelized. Add the thyme and set aside.
Cut the potatoes evenly using a mandolin. Optionally, use a circular cutter to create discs for the top.
Check the stock and add seasoning if needed - this is where most of the flavor of the dish will come from.
Alternate layers of potato and onion, adding some butter and stock in the middle layer.
Top with the discs if desired, and pour in enough stock to just submerge the potatoes. Add some diced butter.
Preheat oven to 360ºF and bake for 45-50 mins. Top with a bit more stock if it starts to dry out on top.