Heat sugar in a large heavy-bottomed saute pan over medium-high heat. Let stand until edge of sugar starts to melt and turn golden. Carefully swirl pan to incorporate all of the sugar. Continue cooking until sugar is a golden-brown caramel, 6 to 8 minutes.
Reduce heat to low, and stir in butter. Add bananas, carefully roll in caramel, and cook, turning bananas occasionally until just soft, 3 to 5 minutes. Remove bananas from caramel, and place in serving dishes. Add 1/2 cup of vanilla ice cream to caramel sauce, and stir until smooth and creamy. Scoop remaining ice cream over bananas, pour caramel over ice cream, and sprinkle with chocolate shavings.
An easy and fast recipe that's good but not fancy. Great for a cozy family dessert after bar-b-que.