Servings: Makes 2 (10- to 12-inch) pizzas, about 12 slices
Note: The white sauce recipe makes 3 cups sauce, more than is needed for this recipe. The remaining sauce will keep covered and refrigerated for up to 1 week. This recipe requires the use of a mandoline for slicing the potatoes thin enough. Inexpensive mandolines ($20 to $25) can be found at most Asian markets and cooking supply stores.
Caramelized onion white sauce
2 tablespoons butter
2 tablespoons olive oil
1 large onion, sliced lengthwise into thin ribbons (about 4 packed cups)
1/2 teaspoon minced garlic
1/4 cup dry white wine
3 tablespoons flour
1 cup milk
1 cup cream
1 teaspoon salt
1/4 teaspoon ground white pepper
1. In a medium, heavy-bottom saucepan, melt the butter with the oil over medium-high heat. Stir in the onion and cook, stirring occasionally, until the onion softens and takes on a golden shade, about 15 minutes. Stir in the garlic and cook just until aromatic, 1 to 2 minutes.
2. Stir in the white wine and cook, scraping any flavoring from the bottom of the pan, until the wine is almost completely absorbed. Sprinkle the flour over the onion mixture and stir to completely coat the onions.
3. Whisk in the milk and cream and bring the mixture to a bare simmer. Continue to cook, stirring constantly (and scraping the bottom of the pan to prevent flour from settling) until the mixture thickens to a sauce, about 3 minutes. Remove from heat, season with the salt and pepper and set aside.
1/2 pound fingerling or other waxy potatoes