Make mango puree using a blender or food processor.
In a small bowl, add mango juice and sprinkle 1 envelop gelatin on top. Wait for a few minutes until gelatin softens. Then mix with a spoon.
Mix the mango puree with the mango gelatin mixture.
Set wine glasses on an angle in a muffin tin. Pour the mixture into glasses to about 1/2 inch below the rim.
Chill in fridge for at least 2 hours to set.
In the meantime, in a small saucepan, add milk and 3 envelopes of gelatin and wait for 5-10 minutes.
Whisk the mixture together, and place the saucepan over medium-low heat.
Add sugar and salt to the saucepan. Mix until the sugar is completly dissolved.
Remove saucepan from heat and stir in heavy cream and vanilla.
Let it cool down to room temperature. Add the mixture to glasses on top of the mango layer. Chill for another 2 hours or until set.