Par cook the potatoes in salted boiling water until they are knife tender.
Heat a large cast iron skillet over medium-high heat.
Add a drizzle of canola oil to lightly coat the bottom of the skillet, then add the butter, par-cooked potatoes and the fresh thyme.
Smash the potatoes into the skillet with the back of a spatula and cook over medium heat stirring every few minutes until they are brown on all sides, about 7 to 10 minutes.
Season well with kosher salt and freshly ground pepper.
Notes
Any baby potatoes can be substituted for marble potatoes.
If cooking the potatoes in a skillet after cooking steak or chicken; leave the fat and juices in the skillet and omit adding the canola oil and butter from the ingredients list.