- Preheat oven to 200C.
- Line bottom of 22cm baking dish with a drizzle of olive oil, 5 thyme leaves, salt and cracked pepper.
- Evenly layer sliced onions then sliced potato and pour simmer stock and butter over the top.
- Finish with remaining thyme leaves, salt and pepper.
- Bake for 35 to 40 minutes at 200 degrees.