POUR milk and orange extract into large bowl. Add dry pudding mix. Beat with wire whisk until well blended. Stir in ricotta cheese. Gently stir in 1/2 of the chocolate.
SPREAD 1/3 of the pudding mixture onto bottom slice of cake. Repeat layers twice, ending with top cake slice.
MICROWAVE remaining chocolate in small microwaveable bowl on HIGH 45 sec. to 1 min. or until almost melted; stir until completely melted. Stir in whipped topping. Spread evenly over top and sides of cake.