Shred the potato and squeeze all the moisture out with a cloth.
Stir together potato, onion, matzah meal, egg, and garlic salt.
Heat a large pan or griddle over a medium-high flame and film with vegetable oil. Spoon small amounts of latke batter onto the hot fat, using a fork to gently spread the mixture to be sure the latkes turn out thin and crispy without a soggy middle.
Only turn the latkes once, so when you see the edges getting browned and crispy it’s time to turn them. Be patient. Turning too early leads to an oily, soggy latke.
Brown on the other side and remove to cookie sheets lined with wire racks. Season with another quick pinch of garlic salt and hide them in an oven at low temperature as you fry the rest.