In 1-quart saucepan, heat 1 cup brown sugar, the whipping cream and 1/4 cup butter to boiling over medium heat, stirring often. Boil and stir 1 minute; remove from heat. Stir in powdered sugar and 1 teaspoon vanilla. Let stand 5 minutes, stirring occasionally. Remove side of springform pan; place cheesecake on serving plate. Pour topping over cheesecake, spreading to within 1/4 inch of edge. Garnish with pecan halves, if desired.