Rich Chocolate Mousse

8 oz Semisweet chocolate
3 tb Powdered sugar
3 tb Hot strong coffee
3 Egg yolks
8 oz Frozen whipped topping; Thawed, divided In a double boiler over simmering water, melt chocolate. Remove top pan from heat; stir in sugar and coffee.
Add one yolk at a time, stirring until smooth.
Place top pan over boiling water; cook and stir for 3-4 minutes or until thick. Pour into bowl; chill 6-8 minutes. Fold in 3 cups whipped topping. spoon into dishes. Top with whipped topping.