Once the salt has been added to the potato mixture, the latkes should be cooked immediately as this will begin to extract further moisture from the potatoes and onions. 

master

Serious Eats

Latkes

russet potatoes

onion

eggs

matzo meal

kosher salt

canola or peanut oil

apple sauce

sour cream

Shred potatoes with food processor, squeezing water out of every 2-3 with cheesecloth as you go. Reserve the water and transfer shredded potato to another bowl. Add diced onion to the potatoes.

Let the potato water stand undisturbed until a slurry forms beneath a layer of water. Drain off the water, then mix the remaining starch into the potato and onion mixture with hands.

Alternate adding an egg, 1/4 cup of matzo meal, and salt until the mixture can be formed into patties that just stick together.

Heat 1/2 inch of oil in a cast iron skillet over medium-high heat until a potato shred immediately bubbles when added to pan. Form a single latke and fry on both sides until golden brown to taste and adjust seasonings as needed.

Form latke mix into patties 4 inches in diameter and 1 inch thick in the center. Fry, no more than four at once, until golden brown on the bottom and flip with a slotted spatula until the same color is achieved on the other side. Flip as needed to get a firm, darker-than-golden crust on both sides.

Transfer cooked latkes to a sheet pan lined with paper towels to cool 2 minutes, then serve with apple sauce and sour cream.