Peel and cut the russet potatoes into cylinders about 1 ½ inch thick.
Warm oven to 320F.
Heat the olive oil in an oven safe skillet over medium-high heat. Add the butter and let it melt.
Place the potato cylinders in the skillet and cook until browned on top and bottom sides, about 5-7 minutes per side.
Add the crushed garlic cloves and fresh thyme sprigs. Cook until fragrant, before garlic burns/gets too golden. Reduce heat.
Pour in the chicken stock avoiding tops of potatoes. Once stock is reduced to about halfway up the potatoes, season with salt and pepper to taste.
Transfer to oven at 320F on the lower rack, uncovered. Let simmer for 20-25 minutes, or until the potatoes are tender and the sauce has thickened.
