Make the waffles: In a bowl, mix together all the dry ingredients. In a separate bowl, using a mixer fitted with the whisk attachment, whip the eggs until they are doubled in size. Add the mashed banana and whip for another minute. Make a well in the center of the dry ingredients and add the milk, oil, and vanilla. Mix just until combined, then fold in the banana mixture.
Use a waffle iron to cook the waffles according to the manufacturer’s instructions, but leave slightly underdone if you’re planning on freezing them.
Make the syrup: Heat the peanut butter and maple syrup together in a small saucepan over low heat.
To freeze: Let the waffles cool, then freeze on a parchment-lined baking sheet. Once frozen, transfer to a labeled gallon-size resealable plastic bag. Toast to reheat and serve.
Note: When you find ripe or overripe bananas on sale, you can mash them all and freeze them in an airtight container (in a portion size for your favorite recipe). Banana bread, muffins, or these waffles are all great uses for frozen ripe bananas.