Set the oven to warm (170°F). Place a cooling rack on a baking sheet.
Peel the onion, quarter it, and process it in the food processor until finely chopped. Place it in a colander, and place the colander on top of a bowl.
Using the fine shredding disc of your food processor, shred the potatoes. Place them in the colander.
Use your clean hands or a large spoon to mix the onion and potatoes. Press on the mixture with your hands or the back of a large spoon repeatedly to extract as much liquid as you humanly can. This is the single most important step in this recipe. The drier the mixture, the crispier the latkes and the less risk of them falling apart. Resist the temptation to add flour to help absorb the liquid; it is unnecessary and will result in suboptimal results.
Whisk the eggs, salt, pepper, and garlic powder in a small bowl.
Place the drained potatoes and onions in a large bowl (you can use the bowl that collected the liquids after pouring them out and wiping the bowl with a paper towel). Add the egg mixture to the drained onion/potato mixture and use a fork to mix well.
Heat the oil in a 12-inch nonstick skillet over medium-high heat until hot but not smoking. The oil should cover the bottom of the skillet and be about ½ inch deep. The oil is hot enough when it gently bubbles around a toothpick placed in the skillet.
Spoon about 2 tablespoons of mixture per pancake into the skillet, pressing on them a little with a spatula to flatten. If using a 12-inch skillet, you’ll be able to fry 4 latkes at a time. I fry in 2 skillets simultaneously – it cuts the frying time in half and is quite doable.
Cook the latkes until their undersides are browned, about 5 minutes. Turn them over and cook until the other side is browned, about 5 more minutes. If the oil becomes too hot, lower the heat to medium. For crispy latkes, you'll want the lacy edges to be brown. Proper brown, not golden brown. The middle can be golden brown.
Transfer the cooked latkes to paper towels to drain, then place them on the prepared baking sheet and keep them in the warm oven while you finish frying more batches.Remix the egg/potato/onion mixture between batches. It tends to separate.
When all the latkes are cooked, serve them with sour cream, applesauce, and (if desired) salsa.
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Notes
I typically use Yukon Gold potatoes. Russet potatoes have an advantage, though - they have a high starch content, which helps the latkes crisp up and also helps prevent them from falling apart when you cook them.
Don't use frozen hash brown potatoes in this recipe. I tried, and it’s just not the same. The latkes turn out much less flavorful and quite soggy. It's best to use fresh potatoes.
The shredded potatoes will quickly darken. That's expected and will not negatively affect the pancakes' taste or texture.
Some of the latkes will cook faster. Remove them to paper towels and add more mixture to the skillet. It's OK to add more uncooked mixture while some latkes are still cooking in the skillet.
You can keep the leftovers in the fridge, in an airtight container, for 3-4 days. Reheat them in a 300°F oven. They won't be as good as fresh, but they will still be quite good. You can also freeze the leftovers in a single layer in freezer bags.