Peel potatoes. (I only peel 2 of the 4. You don't have to peel any at all if you don't want to. Just wash really well.) Grate using a box grater or food processor. You should have 9-10 cups of grated potatoes. Add to a large colander. Toss with 1 teaspoon of salt. Let sit for 15-20 minutes to draw out excess water from the potatoes.
As the potatoes are sitting, go ahead and cut the onion into quarters. Slice the quarters very thinly, add them to the potatoes and allow them to sit together as the salt draws out the water.
At the end of the 15-20 minutes, place about ⅓ of the potato mixture in a cheese cloth or clean, thin kitchen towel, and squeeze out as much liquid as possible over the sink or another bowl. Repeat until all of the liquid has been removed from all of the potatoes.
In a large bowl, whisk together eggs, flour, rest of the salt, pepper, garlic, cornstarch and baking powder. Add the potatoes and onions. Mix well.
For your draining station, place a cooling rack in a baking sheet. Cover the cooling rack with a paper towel and set aside.
Add cooking oil to your skillet, enough to fill the pan about ½ inch. Heat over medium high heat. The oil is ready when you add a bit of potato and it sizzles.
Using a ¼ measuring cup, scoop out the potato mixture and gently place the potatoes in the hot oil. Use a spatula to mash the potatoes out into about a 3 inch circle. (You should be able to add about 4 scoops to your skillet without overcrowding it.)
Cook until the edges begin to brown and gently flip to cook the other side (about 2 minutes on each side). Watch your heat. Turn it down if your pancakes brown too quickly or the oil begins to smoke.
Remove golden browned potato pancakes from the skillet and place them on your cooling rack to drain. Don't stack them. You can also place the cooling rack in the preheated oven to keep the pancakes warm.
Serve warm with sour cream and chives or apple sauce.