Heat two large frying pans over medium heat. Add canola or safflower oil to a depth of ¼-inch. Decrease heat to low, and allow oil to warm as you prepare batter.

Wash and scrub potatoes if you want to keep the skins on, or peel. Grate potatoes using a food processor or hand grater, and transfer to large bowl. 

Grate onions and mix with potatoes in the bowl. 

In a separate bowl lightly beat the eggs and salt. Add to potatoes and mix thoroughly. Mix in flour or matzo meal.

Turn the heat back to medium. The oil is ready when a bit of potato dropped in sizzles. 

Use a ⅓-cup measuring cup to scoop up batter. Drop scoops into hot oil and flatten with the back of a spatula.

Cook latkes until golden brown on one side, about 4 to 5 minutes, then flip and cook second side until golden, another 3 to 4 minutes. Transfer latkes to a plate lined with paper towels to absorb excess oil.

Serve immediately, or keep warm in an oven at 200°F until ready to serve.

Serve latkes with bowls of sour cream and applesauce.