1.Toss the grated potatoes with flour in a large bowl.
2.Stir in mashed potatoes until combined.
3.In a separate bowl, whisk together the egg and skim milk; mix into the potatoes.
4.Season to taste with salt and pepper.
5.Heat the olive oil in a large skillet over medium-high heat.
6.Drop in the potato mixture, forming patties about 2 inches in diameter. Fry on both sides until golden brown, 3 to 4 minutes per side.
7.Drain on a paper towel-lined plate. Serve warm.