Makes 4 servings. You will need 4 small individual baking dishes (about 1 1/2 inches deep and 4 inches across).
Ingredients
2 tablespoons extra-virgin olive oil
1 large yellow onion, sliced thin
6 cloves garlic, sliced thin
2 1/2 pounds Yukon Gold potatoes, peeled
2 cups heavy cream
Salt and freshly ground pepper
1 cup grated pecorino, plus a little extra
1/2 cup coarse bread crumbs, tossed with a little olive oil and minced garlic
4 large eggs
Directions
Heat the olive oil in a medium saute pan. Add the onions and cook until softened and lightly caramelized, about 10 minutes. Add the garlic and a pinch of salt and cook another two minutes. Set aside.
Preheat oven to 325 derees. Season the cream with a good amount of salt and pepper (it should taste a little too salty and peppery). With a mandoline, cut the potatoes into 1/8-inch-thick rounds. Layer the potatoes, slightly overlapping, in the baking dishes. After every other layer, put a little cheese, a little of the onion mixture and pour a little of the cream mixture over the top. When you have filled each baking dish (the unbaked gratins should look very creamy), lightly press down on the potatoes and cover each baking dish with foil. Place the four baking dishes on a baking sheet and bake in the oven for 1 hour, or until the cream is absorbed and a small paring knife easily passes through the center of the gratin. (The recipe can be made up to this point at least two days ahead.)
Turn the heat up to 400 degrees, remove the foil and bake until the tops of the gratins are golden-brown, about 10 minutes. Cool, cover and refrigerate if you are not going to serve within a couple of hours.
When ready to serve, preheat oven to 400 degrees. Break an egg over the top of each gratin, and bake in the oven for about 6 minutes. Remove from the oven, sprinkle generously with cheese and bread crumbs, and return to the oven for another 2 minutes — the gratin should be nice and bubbly. Serve immediately.
