Flourless banana and blueberry pancakes

Ingredients

• 1 cup rolled oats
• 1/4 cup milk
• 1 banana, peeled, plus extra, to serve
• 1 tablespoon baking powder
• 1 tablespoon cider vinegar
• 1 egg
• 1 tablespoon maple syrup or sugar
• 1/2 teaspoon vanilla essence
• 1/3 cup frozen blueberries, plus extra, to serve
• melted butter or cooking spray, for frying
• icing sugar and maple syrup, to serve (optional)