Stand ladyfingers around edge of a 9-inch springform pan; line bottom of pan with remaining ladyfingers, and set aside.
Combine coffee granules and 1/4 cup hot water in a small bowl, stirring until dissolved; let cool completely.
Chop 5 candy bars into small pieces. Stir chopped candy and coffee into ice cream. Spoon into prepared pan. Cover with plastic wrap, and freeze 8 hours.
Stir liqueur into whipped topping, if desired. Dollop whipped topping around edge of ice-cream mixture.
Chop remaining candy bar; sprinkle evenly over top. Release sides of pan. Let stand 30 minutes before serving.
*1/2 gallon coffee ice cream may be substituted for vanilla ice cream.
Note: For testing purposes only, we used Skor English Toffee candy bars.