Melt butter in a 9-inch black iron frying pan over medium heat and immediately add sugar, stirring constantly with a wooden spoon. Cook until it is golden caramel in color but be sure to remove the pan from the heat before the caramel is too dark, as it will continue cooking from the pan heat.

Cut the pears in half lengthwise, core and peel them, and gently toss the pears with the liqueur of your choice if used. Arrange the pears in the caramel rounded side down and pointed end towards the center.

Cut four or five 1-inch slits in the center of the pastry to allow steam to escape, and lay it over the top of the pears. If you're using frozen pastry let it defrost first <G>. Push the pastry down between the pears and the sides of the pan. This will make a nice, wavy edge as the pastry conforms to the shape of the pears.

Set the tart in the middle of a preheated 400 deg F oven and bake for about 30 minutes, or until the pears are tender and the crust is browned and baked through. Remove from the oven, let stand for a minute and then invert a serving platter over the top of the pan. Lift the two together, holding the platter as tight as you can against the baking pan, and flip it over quickly so the juice doesn't splatter. If a lot of the caramel has run off, spoon it back over the pears.

Serve with vanilla ice cream or creme fraiche - serves 8