Place ham in a heavy duty zipper-lock bag or a sous-vide bag
Add bagged ham to preheated water bath and cook for at least 6 and up to 12 hours.
Heat half the oil in a large skillet or griddle over medium-high heat until shimmering
Add ham and cook, pressing down with a stiff spatula or griddle press, until well-seared and crisp, about 2 minutes.
Do not sear second side. Transfer to a warm plate and repeat with remaining oil and ham. Serve immediately.