1. Whisk together flour, sugar, baking powder, and cinnamon in medium bowl. Lightly beat egg in separate bowl, then whisk in milk and oil until well combined. Gradually add flour mixture to egg mixture until just combined, adding more milk or water if necessary to thin batter.
2. Heat griddle or skillet over medium heat. Coat with cooking spray. Ladle about 3 Tbs. batter for each pancake onto griddle. Place 3 or 4 banana slices on each pancake. Cook 2 minutes, or until surfaces of pancakes are covered with bubbles. Flip, and cook 1 minute more, or until both sides are golden brown. Repeat with remaining batter.