Blend or process lucumas until soft and smooth. Force through a fine sieve and set aside.
Whip egg whites until foamy, add ½ cup sugar and continue beating until thick.
Beat cream until thick as for chantilly.
Soften gelatine in water and heat until dissolved. Add sugar and combine.
Add warm gelatine to lucuma mixture. Fold in egg whites, carefully.
Fold in whipped heavy cream and vanilla extract.
Lightly oil a tube cake pan and pour in preparation. Refrigerate until firm.
To unmold run a knife around the edge and invert mold onto serving plate.
Optional: Serve bavarois with Pastry Cream.
Fresh lucuma substitution:
2 pounds of fresh lucuma = 4 tablespoons dehydrated lucuma powder.
Soak lucuma powder in the same quantity of liquid 2 or 3 hours before using it. Stir. It will have the consistency of a puree.