Pare potatoes with a vegetable peeler. Grate potatoes
on medium grater into a large bowl. Add onion, salt,
and pepper and mix lightly but well with a blending
fork. Melt margarine in a 10-inch frying pan and
rotate to coat bottom and sides of pan. Turn potatoes
into pan; pat down and spread evenly. Cover pan
tightly; turn heat low and let cook about 15 minutes
or underside is browned. Take pan off heat
temporarily. Put a 12-inch plate (or very large pie
plate) unside down on top of potatoes and, with one
hand handle of frying pan and the other hand guiding
the plate, turn frying pan unside down, then lift off
the pancake. This put the pancake back on the plate.
Next, immediately slide pancake back into the frying
pan, browned side up. Return to low heat. Do not
cover. Let cook for another 15 minutes or until bottom
is browned. To serve, cut evenly into 6 pie-shaped
wedges.
