Trim fat from meat. Cut meat crosswise into 1-inch-thick slices. Place each slice between two pieces of plastic wrap. Use the flat side of a meat mallet to lightly pound each slice into a 1/4-inch-thick medallion. Remove plastic wrap.
In a shallow bowl combine flour, salt, and pepper; coat meat with flour mixture. In a large heavy skillet heat olive oil over medium-high heat. Add meat, half at a time, and cook for 2 to 3 minutes or until meat is slightly pink in center, turning once. (Add more oil, if necessary.) Remove from skillet.
In the same skillet cook pancetta over medium-high heat until crisp. Add fennel, onion, and garlic. Cook for 3 to 5 minutes or until crisp-tender. Add lemon juice; stir in whipping cream. Bring to boiling; return meat to pan. Cook until meat is heated through and sauce is slightly thickened. Transfer the meat to a serving platter. Spoon the sauce over the meat.