1. Shred potato and onion using the shredding blade of a food processor. Combine shredded potato and onion in a colander over a large bowl, tossing well to combine. Let mixture stand 15 minutes, pressing occasionally with the back of a spoon until most of liquid drains off. Remove colander from bowl. Carefully pour off the potato liquid, reserving thick white layer of potato starch in the bottom of the bowl. Discard potato liquid.
2. Combine egg substitute, flour, salt, and pepper in a small bowl, stirring with a whisk. Add egg mixture to potato starch in large bowl, stirring well with a whisk to combine. Add potato mixture and parsley to bowl, tossing well to combine.
3. Heat a 12-inch nonstick skillet over medium-high heat. Add 1 1/2 tablespoons canola oil to pan, swirling to coat. Add potato mixture in 1/4-cupfuls to pan to form 6 latkes; flatten slightly. Cook 4 minutes on each side or until golden brown. Remove latkes from pan; keep warm. Repeat procedure with remaining 1 1/2 tablespoons oil and remaining potato mixture.