Preheat your oven to 400 degrees F. Grease a 2 quart casserole.
Peel and rinse the potatoes. Trim the onion into chunks. Using a food processor, grate the potatoes and the onion. Transfer to a large bowl and toss with 1 tablespoon salt.
4 lbs potatoes, 1 onion, 1 tablespoon salt (for pulling out moisture during squeezing)
Put ⅓ of the potato mixture into the center of a large linen towel. Bring the ends of the towel together and twist the ball of potato mixture tight so that the water drips out into another bowl. Empty the squeezed potato mixture into a mixing bowl. Repeat until all the potato mixture is squeezed.
It the bowl of potato liquid, the white starch will settle to the bottom. Drain off the clear liquid, and save the starchy portion to add back to the bowl of squeezed, grated potatoes.
Whisk together the eggs, 1 teaspoon salt, and ground pepper. Pour into bowl of squeezed, grated potato mixture. Stir to blend.
1 teaspoon salt (for cooking), 6 eggs, ½ teaspoon black pepper
Add the potato and egg mixture to the prepared casserole. Place in oven to bake for 55 minutes. Top should be crispy and center will be tender. Garnish with chopped chives or green scallions, and serve while hot with sour cream or applesauce.
3 tablespoon olive oil, 2 tablespoon chives