In a large skillet melt the butter and the sugar. Add the banana slices, sauté for two to four minutes or until golden brown. Using a slotted spoon place the bananas in four serving dishes, reserving the remaining butter mixture in the pan.
Add the half-and-half to the butter mixture and simmer for 4-6 minutes until thickened. Remove from the heat and stir in the vanilla.
Pour the sauce over the bananas and serve immediately.