1 tablespoon unsalted butter
1 pound fresh Italian sausage or chorizo
3 pounds sweet potatoes, about 3 large potatoes, ideally organic
6 large garlic cloves
4 long stalks rosemary, about 1/4 cup of leaves
3 tablespoons olive oil
1 tablespoon kosher salt, plus more to taste if necessary
Freshly ground black pepper
Kosher salt and freshly ground black pepper
Parmesan cheese, to serve
Heat the oven to 450°F. Peel the onions and cut them in half lengthwise, then cut them into thin half-moons. Cut the half-moons in half. Melt the butter in a skillet over medium-high heat. When it foams up add the onions and sprinkle lightly with salt. (Don't worry if they are crammed into the pan; they will rapidly cook down.) Lower the heat slightly and cook the onions for about 30 minutes, stirring occasionally, and lowering the heat if they seem to be burning. Cook them until they are very dark brown.
Heat the oven to 425°F. Spread a relatively thin layer of the (already cooked) sweet potato hash in a baking dish, such as a cast iron skillet or a 9x13-inch baking dish. You can also bake in individual ramekins. Make small wells in the sweet potatoes and crack in large eggs. Sprinkle lightly with salt and pepper.