Grate potatoes and onion in food processor and transfer to large bowl, or grate the potatoes and onion by hand directly into a large bowl.
Add remaining ingredients to make a thick batter. If the batter is too thin, add more bread crumbs until you can easily pick the batter up in your hands.
Form into 4 to 6 pancakes.
Heat a skillet with 2 tablespoons unsalted butter or regular margarine or vegetable oil until the fat is hot. Add the croquettes a few at a time in order not to crowd the skillet.
Cook on both sides until brown and thoroughly cooked. Sprinkle with salt and pepper.
Keep warm on paper towels in a very low (200 degree) oven.