Choose yellow (firm-ripe) bananas. Cut them in half crosswise. Spray a small square nonstick cake pan with cooking spray. Preheat oven to 450 degrees. Put the butter in the pan; place in the hot oven just long enough for butter to melt.
Place the bananas in the pan and tilt the pan so the bananas roll and become lightly coated with butter. Place the pan on the bottom oven shelf and bake only 5 minutes, turning the bananas once, until just browned. Serve with salt and pepper as a starchy side dish, or sprinkled with cinnamon and sugar substitute as a dessert.
