Chop your onion by hand very finely and place in a large bowl.
Prepare a bowl with water and ice cubes in it. After grating your potatoes (by hand/food processor), thinly or thickly depending on preference, put them in the bowl.
Drain the grated potatoes in a salad spinner or wrap them in a clean towel a few handfuls at a time and wring out the towel very well (over the bowl of water) until not a drop of water is left.
Quickly add the potatoes to the bowl of onions. Add remaining ingredients and mix well.
Heat a heavy cast iron skillet or stainless steel pan. Add oil for frying – any oil that won’t burn easily at high heat, such as canola, peanut, or corn oil. Allow to heat up to the point at which it shimmers and thins out. Turn the heat to medium/high.
Fry, using about 1/4 cup of batter per latke. Remove the latkes to paper towels to drain. Allow 30 seconds or so between batches to let the oil heat back up to right temperature, especially if you’re adding oil.
Serve with a dollop of sour cream and/or applesauce on top or on the side. Sprinkle with chopped chives or parsley if desired.