Grate the potatoes, and mix with the onions and garlic.
Place a cheesecloth over a colander, and add the mixture to it. Sprinkle with salt, and let it sit at room temperature for about 30 minutes to drain excess moisture.
Squeeze out any more moisture that you can with the cheesecloth when it’s ready.
Add the lemon zest, breadcrumbs, and Parmesan to a large bowl and season with salt and pepper.
Beat the egg yolks lightly, and add to the breadcrumb mixture along with the lemon juice and potato mixture. Mix together.
Add the chopped scallions, and stir into the mixture.
Heat the oil in a large skillet with a heavy bottom. It should cover about 1/4-inch. Heat at a medium-high setting.
It’s ready for the latkes when a bit of the batter sizzles the second it touches the pan.
Use about 1/2 cup of the latke batter for each one, using the back of a spoon to make them into rounds about 1/2-inch thick.
Fry for a few minutes on each side, shaking the pan slightly or moving them a little to prevent sticking. Cook until the edges are solid on one side before turning.
When both sides are golden brown, place them on a baking sheet in the oven at about 200 °F to keep warm. Repeat until all of them are cooked.