Prepare the flavored jelly according to package instructions and set aside to cool.
Whip the heavy cream with sugar and vanilla extract until soft peaks form.
In a separate bowl, dissolve the gelatin in warm water.
Mix the dissolved gelatin into the whipped cream gently.
Pour a layer of jelly into a cake mold and refrigerate until set.
Once set, add a layer of the whipped cream mixture on top.
Repeat layering jelly and cream until the mold is full.
Finish with a layer of jelly on top and refrigerate until fully set.
Carefully remove the cake from the mold.
Decorate with fresh berries before serving.