In a large, deep ovenproof skillet, heat the 1 teaspoon of olive oil. Add one-third of the pancetta and cook over moderate heat until crisp, about 7 minutes. With a slotted spoon, add the pancetta to the prunes. Add the garlic to the skillet and cook over low heat for 1 minute. Scrape the garlic into the bowl. Add the bread crumbs, chestnuts, chopped rosemary, pecorino and cayenne and season with salt and pepper. Stir in the eggs.