Melt the butter on medium heat in a saucepan just large enough to hold the pear slices in one layer. Add the pears and cook for two minutes, shaking the pan occasionally. Turn them over and cook for one more minute.
Remove the pears and arrange them on the salad plates.
Add the vinegar to the pan and return it to the heat. Simmer the vinegar for three minutes to reduce it and incorporate the flavors left in the pan. Remove from the heat and stir in the olive oil. Pour a little of the warm dressing on each of the salads and serve immediately.
Makes 6 servings.