It is best to fry in small batches, rather than crowding the pan with too many potatoes at once.
Line a baking sheet with paper towels.
Cut the potatoes into 1/4- to 1/2-inch slices.
Add approximately 4 to 5 inches of oil to a deep, heavy frying pan or saucepan. Heat to 325°F, using a deep-frying thermometer to check the temperature.
Add sliced potatoes and cook, turning once or twice, until they are almost tender but still pale and waxy looking, approximately 6 to 8 minutes.
Using a slotted spoon, transfer the potatoes to the paper towel-lined baking sheet to drain excess oil.
Season generously with malt vinegar sea salt , BBQ rub, and if desired, Kosher salt.