Melt 4 tablespoons butter in a small skillet over medium heat on the stove or in the microwave and set aside to cool slightly
Whisk together 1 1/2 cups all purpose flour, 3/4 cup whole wheat flour, 2 tablespoons sugar, 2 tablespoons protein powder, 1 tablespoon baking powder, 1/4 teaspoon baking soda and 1/4 teaspoon salt in a large bowl.
Whisk together 2 1/2 cups milk and 1 teaspoon vinegar in a separate large bowl and let sit for a couple minutes to sour.
Whisk in 2 mashed bananas, 2 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.