Using a hand or standing mixer, mix the bananas, peanut butter (1 cup), honey (1/4 cup), cinnamon (1 teaspoon, optional), and vanilla extract (1 teaspoon, optional) until very smooth.
Add oats (2 cups) and almonds (1 cup) and mix until combined.
Turn out onto a parchment covered baking dish (about 9×9 inches). Press and flatten with a spatula until evenly distributed.
Bake at 350 degrees for 30 minutes, or until golden brown on edges.
Allow to cool completely before cutting bars.
Store at room temperature for a week or freeze for up to 6 months in an airtight container or wrapped individually in plastic wrap.