Using a food processor with the grating disc, grate potatoes, carrots and onion. Transfer to large mixing bowl, and press to drain any excess liquids.
Beat eggs, and add to bowl. Add cornstarch, salt, and pepper, and toss to coat completely.
Heat oil in a large frying pan or skillet on medium heat. Use a 1/2 cup measuring cup to scoop out batter. Flatten, and fry for 3-4 minutes per side. Repeat until all batter is fried (stir with a fork before scooping each batch if ingredients have separated).