Lightly spray a coat of “de-mold spray” into the molds ( for resources for the de-mold spray and the molds).
Warm the cold guava purée to 15°C/60°F over a warm water bath. Reserve at room temperature.
Make an Italian meringue by combining the first amount of sugar with one-quarter of its weight in water in a small sauce pot. Cook the sugar to 118°C/244°F. Meanwhile, whip the egg whites to stiff peaks.
Once the sugar has reached the correct temperature and the egg whites have reached stiff peaks, pour the sugar into the egg whites as they whip on mediumhigh speed. Continue to whip until the meringue cools to room temperature.
Combine the heavy cream, second amount of sugar, and the heavy cream stabilizer in an electric mixer bowl on medium-high speed and whip until it reaches medium-soft peaks. Reserve refrigerated.
Place 10 percent of the tempered guava purée and the bloomed gelatin in a small bowl. Place the bowl over a hot water bath and stir until the gelatin dissolves. Pour this mixture into the larger amount of guava purée.
Fold in the Italian meringue in 2 additions. Fold in the whipped heavy cream in 2 additions. Fold in the white chocolate-coated puffed rice.
Pour the guava cream into a piping bag. Follow the instructions for assembling the cakes.