Preheat the oven to 180C/350F. Line a loaf pan with parchment paper and set aside.
In a large mixing bowl, add the mashed bananas, milk, vinegar, and vanilla extract and mix until combined.
Gently add the self rising flour, almond flour, protein powder, sugar of choice, and mix until smooth.
Transfer the batter to the lined pan and bake for 45-55 minutes, or until a toothpick comes out mostly clean from the center.
Remove the bread from the oven and let it cool completely, before removing from the pan and slicing.
