Peel potatoes and onion, then grate finely using a box grater. Place potatoes in a clean kitchen towel and wring out excess moisture, then place in a large bowl with flour, matzo meal, salt, pepper, and eggs and mix well without kneading. Heat schmaltz in a large frying pan until shimmering. Form 2-inch patties with the mixture and fry in olive oil until golden on the first side. (If patties are too dry to hold shape, add 1 more egg.) Turn to second side and fry until golden. Season after frying with salt and place on a sheet pan. Repeat until all patties are made. Bake at 350° F degrees for 12 minutes. Serve immediately with sour cream.
Latkes reheat beautifully. To do so, store refrigerated in an airtight container. To warm, place latkes on a sheet pan and heat in 350 degree oven until warmed through, about 6-8 minutes, add cheese after reheated.
For the pear sauce:
In a large saucepot, combine pears, cider, and sugar. Scrape vanilla bean into pot and add vanilla pod. Simmer until pears are soft, then remove pears, leaving remaining liquid behind. Simmer remaining liquid until reduced to syrup. Process pears through a food mill or food processor until smooth, then add syrup, a few scrapes of fresh nutmeg, zest of 1/3 orange, and salt to taste