Preparation
Peel mango then slice fruit from pit; cut into 1/2-inch chunks. Peel and halve the papaya then scrape out the seeds; cut it into 1/2-inch chunks; toss with the mango and set aside. If using berries, rinse and pat dry with paper towels; slice strawberriesand set aside to top pancakes.
In medium bowl, mix together flour, sugar, baking powder and salt. In a large bowl, whisk together banana, milk, egg and walnuts. Stir in dry ingredients just until moistened; some lumps in the batter are okay. If the batter seems too thick, add a bit more milk.
Heat griddle or skillet, preferably nonstick, until medium hot (a few drops of water sprinkled on it will sputter before evaporating). Brush with a little oil. Spoon the batter onto the griddle, using about 1/4 cup per pancake. Cook about 2 minutes, until the surface is dry and full of bubbles, then turn and cook up to 1 minute longer or until golden brown. Keep pancakes warm in low heat oven.
Serve pancakes hot with prepared fruit and drizzle with maple syrup or honey, if desired.