PREPARE cake mix according to package directions for 13 x 9-inch baking pan; cool completely in pan on wire rack.
PLACE sweetened condensed milk in a large, microwave-safe bowl. Microwave on MEDIUM power, stirring halfway through, for 4 minutes. Reduce to MEDIUM-LOW power; microwave, stirring with wire whisk every few minutes, for 16 to 24 minutes or until thick and light caramel colored. Stir in caramel topping. Cool for 15 minutes. Spread evenly over cake. Cool completely.
BEAT cream in a large mixing bowl until soft peaks form. Add sugar and vanilla extract; beat until stiff peaks form. Spoon over cake; sprinkle with almonds. Refrigerate for 1 to 2 hours.