Lay out your romaine lettuce, using each large leaf as a wrap.
Place a piece or two of proscuttio on each leaf.
Put a tablespoon of kraut on each wrap. Note: I usually used canned sauerkraut for everything, but for these, I'll spring for a flavored or pickled type like the kinds made by Osuke.
Top with mustard. Roll up for a quick and portable meal.