To begin, put a 9×13 baking dish or pan in your oven and preheat it to 400 degrees. You want to use a metal or cast iron dish if possible for the best results.
Wash and peel the potatoes, then use a food processor or hand grater to grate them into large shreds. As you shred them, put them in a large bowl and cover the shredded potatoes with cold water.
Let the potatoes sit a few minutes while you prepare the rest of the ingredients.
Melt the duck fat in a small skillet or saucepan. (See note)
Peel the red onion and cut it in half. Dice one half of the onion and shred, or grate, the other half. (You can also grate it all for more onion flavor, or dice it all for a little less.)
In a mixing bowl, whisk together the eggs, salt, and pepper until they are nice and fluffy.
Pour the potato shreds into a colander. Push down and squeeze every bit of liquid out that you can.
Place the drained potatoes in a large mixing bowl. Sprinkle the potato starch over the potatoes and give them a quick tossing with your hands to coat the potatoes.
Add the seasoned eggs, diced and grated onion, and toss them all again to mix the ingredients together.
Take your preheated baking dish out of the oven. Pour half of the melted duck fat into the hot pan and spread it all over the bottom with a basting or pastry brush.
Immediately add the potato mixture to the hot pan and hear that lovely sizzle! Spread the potatoes all out evenly in the pan.
Use the brush to spread the remaining duck fat all over the top of the potatoes.
Bake uncovered for 60-70 minutes, or until the top is nicely browned on the top. If you think it is getting browned too quickly as it bakes, simply tent the pan with some foil. The top should be nicely golden.
If when the kugel is done baking, you want it a little more browned, pop it under the broiler for a couple minutes. Let it rest for 5-10 minutes before serving.
Potato Kugel is great plain, but you can also serve it with sour cream and minced chives or scallions.
Enjoy!
Notes
If you do not wish to use duck fat, you can also make this with melted butter or you can use extra virgin olive oil.