In a small, heavy saucepan, combine the sugar, egg yolk, and vinegar. Warm over low heat, stirring constantly, until the sugar dissolves and the mixture thickens. Remove from the heat and mix in the Miracle Whip.
Combine the bananas and peanuts in a large bowl. Spoon the dressing over the salad and mix well. Top with additional peanuts if you wish. The salad is