In a  bowl, mix together cake mix, guava juice, eggs, and oil until together for 2 minutes with a hand mixer.

Spray a 9x13 glass baking dish with non-stick cooking spray and bake according to cake mix package directions.  Allow cake to cool before adding the next layer.

For the cream layer -  In another bowl, beat cream cheese with hand mixer until fluffy. Add sugar and vanilla; mix well.

Next fold in the Cool Whip and spread over the cooled cake. Place in the refrigerator while you make the guava layer.

For the guava layer - In a medium saucepan, bring the 2 cups guava juice and sugar to a boil.

Mix the cornstarch and water together well in a small bowl. Remove guava juice from heat and stir in the cornstarch mixture.

Return to heat and bring back to a boil and boil for one minute. If desired, add a drop of food coloring to make the guava layer pink. Mine was more of an orange collor and needed the food coloring.

Allow the guava mixture to cool. While cooling, stir it ocassionally to help it cool down faster.

When the guava layer has cooled, spread it over the top of the cream layer of the cake. Refrigerate the cake until ready to serve. Serves 12.