How to Make It
In a large bowl, mix the egg with the flour, salt and white pepper. In a colander, toss the shredded potatoes with the onion and apple and squeeze dry. Add to the bowl and stir to combine. Set aside for 10 minutes.
In a large skillet, heat 1/2 cup of canola oil with 2 tablespoons of the schmaltz until shimmering. Spoon heaping tablespoons of the latke mixture into the oil about 2 inches apart and flatten slightly with a fork. Fry the latkes over moderately high heat until golden on the bottom, 2 to 3 minutes. Lower the heat to moderate, turn the latkes and fry until golden and crisp, about 2 minutes longer. Drain the latkes on paper towels set on a rack and transfer to a platter. Repeat with the remaining latke mixture, adding more oil and schmaltz to the skillet as needed. Serve hot with Vanilla Apple Sauce and sour cream.
To make schmaltz, use the large clumps of fat from the neck, body cavity, and from under the skin. In a small, heavy saucepan, cook the fat over low heat until completely melted. Cool, then strain the clear fat into a glass jar and refrigerate for up to 1 week or freeze.