To prepare pancakes, lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and the next 6 ingredients (through farina) in a large bowl; stir with a whisk. Combine buttermilk, oil, vanilla, and egg; add to flour mixture, stirring until smooth. Fold in banana.
Spoon 1/4 cup batter per pancake onto a hot nonstick griddle. Turn when tops are covered with bubbles and edges look cooked.
To prepare syrup, combine 1/2 cup juice and syrup in a medium saucepan. Bring to a boil over medium-high heat. Combine 2 tablespoons juice and cornstarch in a bowl; add to pan. Cook 1 minute or until thickened; remove from heat. Serve with pancakes.