In medium bowl, combine flour, sugar, baking powder, baking soda, and salt. Stir with fork or whisk well to blend and get out any lumps. With spoon, stir in chocolate chips. Set aside.
In small bowl, combine egg, oil, and vanilla. With fork, beat to mix well. Wash, dry, and peel bananas; remove any dark spots. In food processor fitted with steel blade, puree peeled bananas to make a smooth, thick puree. Add to egg mixture along with milk. Beat with fork to combine. All at once, add liquid ingredients to dry ingredients. Stir (do not beat) only until ingredients are well-combined. Do not overmix; batter should be slightly lumpy.
Over medium heat, preheat griddle until drops of water thrown onto it sizzle and "dance", or move around rapidly before evaporating quickly. If griddle is not nonstick, grease with small amount of butter (repeat greasing as necessary while cooking). For each pancake, drop about 2 tablespoons of batter onto preheated griddle. Leave room between pancakes to allow them to spread while cooking.
Cook pancakes on first side until edges appear "set" or cooked, pancakes are puffed up, and some bubbles that break on the top (uncooked surface) do not fill back in with batter. Flip over; cook until second side is golden brown. Serve immediately or keep warm in a low oven while remaining batter is cooked. Serve with warmed preserves or syrups and sieve a bit of confectioners' sugar on top.