Preheat oven to 350 degrees.

Grate the potatoes and onion into a large bowl.

Pour 1 cup of vegetable oil, breadcrumbs, salt and pepper into the potato and onions. Mix to combine well. 

Grease a 9 x 13 inch casserole dish with 1 tablespoon of vegetable oil.

Evenly place the yapsuk mixture into the casserole dish. Cover the dish with aluminum foil and bake for 40 minutes. Remove the yapsuk from oven and raise the temperature to 400 degrees. Uncover the yapsuk and transfer it back into the oven for 1 to 1 ½ hours until the potatoes are cooked through and the edges of the yapsuk are a deep golden brown.

Serve hot with a side of gravy.