No special sauce needed for these pears; just mix a little vanilla ice cream with the pear juice.
Peel 4 firm, ripe Bosc pears, and core from the bottom using a melon baller, leaving stems intact. In a 2-quart microwave-safe dish with a lid, place 2 tablespoons light-brown sugar and 1 tablespoon unsalted butter, and add pears. Cover, and microwave on high until the pears are tender enough to pierce with a knife, 10 to 12 minutes (timing will vary depending upon ripeness of pears). Don't be concerned if pears fall over on their sides as they cook. Carefully uncover, as dish lid will release steam.
Transfer cooked pears to 4 shallow serving bowls, leaving juices behind. Add 1/4 cup vanilla ice cream to the juices in the dish; stir until smooth and saucy. Dividing evenly, spoon sauce around the pears; serve at room temperature or chilled.
You can serve these warm, or you can make the pears and the sauce, store them separately in the refrigerator, and serve chilled.