In a large bowl, mash ripe bananas well. Whisk in egg, vanilla, milk, vinegar, and oil.
Add in flour, sugar, salt, and baking powder. Whisk until batter is mostly smooth. (A few lumps are ok!)
Preheat a lightly greased nonstick skillet or griddle over medium-medium low heat. Using a 1/4 cup dry measure, pour batter onto hot skillet and spread into a 4-inch circle. Sprinkle mini chocolate chips and chopped walnuts onto the tops of the pancakes. Flip when bubbles start to form on the pancake surface and the bottom is golden brown. Cook another minute or until the bottom is also cooked. Remove from the hot pan.
Repeat the process until no more batter remains. Serve warm with sliced bananas, extra chocolate chips, walnuts, and real maple syrup.
*optional add-in: 1/2 teaspoon ground cinnamon... it's so good!!