In a medium-sized saucepan, boil the puree, simple syrup and lemon juice. Whisk in the bloomed gelatin. Pour into a medium-sized bowl, set aside to cool.
When cool, pour 150 grams into a Silikomart silicone hemisphere mold with a diameter 6.26 inches (15.875cm).
Freeze the gelee. Remove it from the mold just before you assemble the ca