Pre-heat oven to 350°F.
Peel potatoes and shred with box grater or food processor.
Transfer to a kitchen towel and squeeze to remove excess liquid.
In a large bowl, whisk eggs, bread crumbs, flour, milk, salt, baking powder and pepper.
Add potatoes and onions and mix until well coated.
Heat the schmaltz and oil in a large sturdy skillet (if not using schmaltz, use 5 tablespoons oil) over medium-hight heat.
Once the oil is hot, add spoonfuls of the latke mixture and gently flatten with your finger or back of a spoon.
Cook until golden on the bottom, about 3 minutes.
Gently flip with a spatula, and cook the other side until golden.
Remove to paper towel-lined plate and finish the remaining latkes, cooking in batches, if necessary.
Keep cooked latkes in warmed oven.
Serve with applesauce and sour cream.