Add mango juice to a medium saucepan and sprinkle the gelatin over it. Let it sit for 1-2 minutes. Turn the stove on, and on low heat stir in the sugar into the juice and gelatin mixture. Cook stirring for 3-5 minutes, just until all the sugar and gelatin have dissolved.
Transfer the mixture to a glass bowl and cool to room temperature.
Add 1 cup of mango chunks to a food processor and process until smooth.
Whisk the heavy whipping cream on high speed until stiff, when soft peaks have been formed, reduce the mixer speed to low, and add the mango gelatin mixture to it. Whisk on low until combined. Make sure to scrape the sides of the bowl with a spatula, to make sure the mixture is fully combined.
Stir in the remaining 1 cup of mango chunks into the mixture.
Place one yellow cake layer into the center of a 9 or 10-inch springform pan, there will be space around it. Pour the mousse over the cake letting it fill in around the side. Refrigerate at least for 2 hours before adding the strawberry jelly layer.
NOTE: if you have a higher springform pan, or a cake ring form, pour half of the mousse over the cake layer, chill, then top it with the second layer, and cover with the remaining mousse mixture.