Wash your hands well with soap and warm water for at least 20 seconds.
Rinse blueberries if using fresh.
Spray a half sheet pan (13” x 18” x 1”) with vegetable oil cooking spray.
In a large mixing bowl combine flours, baking powder, sugar, and salt.
In a small mixing bowl combine eggs, vegetable oil, and milk.
Add the egg mixture into the flour mixture. With a plastic spatula, gently stir from the edge of the bowl to the center of the bowl, scraping the es and folding the ingredients together until well mixed.
Pour the batter into the sheet pan, then top the batter with the blueberries and sliced bananas. (Or add the fruit into the mixing bowl then pour batter into the sheet pan.)
Bake 13-18 minutes, or until golden on top. Cut into a 4 x 5 grid (yields 20 squares) and serve.