In a large bowl, mash banana with a fork until smooth.
Add almond butter, maple syrup, and vanilla and mix.
Add protein powder, almond flour, and cinnamon and mix again. A thick dough should form.
Add oats, walnuts, and salt and mix again. It may be easier to mix with your hands at this point.
Roll dough into about 15 1-inch balls. Store in an airtight container in the fridge.
Notes
These will keep in the fridge for about 3-4 days. They freeze well, so if you don’t plan on eating all of them right away, I recommend freezing some!