Remove roots, outer leaves, and tops from leeks, leaving 8 inches of each leek.
Cut each leek in half lengthwise to, but not through, root end. Rinse under cold water; drain. Tie leeks securely with string.
Place leeks in a medium saucepan. Cover with water; bring to a boil. Reduce heat; simmer, uncovered, 15 minutes or until tender. Rinse leeks under cold water; drain and squeeze dry. Discard string. Finish cutting each leek lengthwise through root end; cut each half crosswise. Wrap each quarter with a slice of ham.
Place each ham roll into a 13 x 9-inch baking dish coated with cooking spray.
Pour Bchamel Sauce over ham rolls; sprinkle with cheese.
Bake at 350 for 25 minutes. Broil 3 minutes or until browned.
