Melt butter in a small skillet over medium heat on the stove or in the microwave and set aside to cool slightly
Whisk together both flours, sugar, protein powder, baking powder, baking soda and salt in a large bowl.
Whisk together milk and vinegar in a separate large bowl and let sit for a couple minutes to sour.
Whisk in mashed bananas, eggs and cooled melted butter, then dump the dry ingredients into the wet and whisk just until evenly moist. Let sit 10 minutes to thicken.
Heat a large cast iron or non-stick frying pan over medium heat. Spray with a generous amount of cooking spray. Working in batches, spoon 1/2 cup batter for large 6-inch pancakes into the pan. Cook pancakes until the edges have begun to brown and air bubbles cover the top, about 3 minutes. Flip pancakes and cook 1 to 2 minutes more. Repeat with remaining batter, spraying the pan before each batch.
Serve while still warm with the spiced prune syrup, fresh fruit, peanut butter, and/or butter.