The Preparation
Heat oven to 425°F.
Pat potato cylinders completely dry.
Heat oil in an oven-safe skillet over medium-high until shimmering.
Salt the tops of the cylinders generously.
Lay potatoes flat-end down.
Press gently for full contact.
Do not touch for 5–7 minutes.
Flip.
Sear the other flat end another 5–7 minutes until deeply golden.
Add thyme, garlic, and 2 tbsp butter.
Baste briefly.
Pour warm stock around (not over) the potatoes, about two-thirds up the sides.
Add remaining butter.
Transfer to oven, uncovered.
Braise 30–35 minutes until stock is mostly absorbed and potatoes are tender through.
Rest 2 minutes.
Plate and serve immediately.
The Chef's Notes
Patting the potatoes completely dry before searing is non-negotiable — surface moisture prevents the Maillard crust from forming. Warm the stock before adding it so it does not drop the pan temperature.