Combine the flour, salt and egg in a large mixing bowl. Add 2 cups water and beat with a whisk for 5 minutes or until very smooth. Quickly stir in the remaining water. Allow to stand 1 hour. (The batter will appear very thin, almost milk-like -- this is fine.) Stir together 1/4 cup lardo, pancetta, garlic, rosemary and black pepper in a mixing bowl until smooth and set aside.
To cook the borlenghe, heat a 14 to 16-inch non-stick pan over medium heat and brush with 1/4 teaspoon of the remaining lardo. Pour enough batter to just coat the pan (just like a crespella) and return to heat. Cook 4 minutes on the first side and turn carefully. (The texture will not be like a crespella, or anything else, for this is an original and distinct delicacy. It may crack, but keep going.) Continue until all the batter is finished, or about 10 to 12 borlenghe.
To serve, reheat borlenghe quickly in the same pan, spread with 1 tablespoon pancetta mixture, sprinkle with grated cheese and serve warm, folded into quarters.
Recipe copyright 2000, Mario Batali. All Rights Reserved.