To Make Trifle:

1. In a trifle bowl or small glass, add a layer of the chopped Twix bars. Then use a pastry bag (or a Ziplock bag with the corner tip cut out) to pipe in a layer of caramel mouse. Then do the same with a layer of chocolate fudge sauce. Then repeat! Finish of with a layer of whipped cream, and top with the remaining Twix bars. Serve immediately or refrigerate up to 8 hours.

To Make Salted Caramel Mousse:

1. Briefly stir together granulated sugar and water in a small saucepan, then bring to a boil over medium-high heat. Continue cooking, without stirring, until mixture turns dark amber in color, about 6 to 7 minutes. (Keep an eye on it, though, because it goes from clear to amber very quickly!)
2. Remove from heat and slowly add in cream (just start with a tablespoon or two), stirring with a wooden spoon until completely smooth. (Be careful, as the mixture will definitely bubble up and possibly splatter a bit as you add in the cream.) Stir in vanilla and salt. Set aside until it reaches room temperature, or refrigerate to speed up the process.
3. In the bowl of a stand mixer, beat PHILADELPHIA Cream Cheese on medium-high speed for 1 minute until very smooth. Add in the room-temperature caramel and powdered sugar, and beat on medium-low speed until combined. If the mousse is too thick, add in a tablespoon or two of heavy cream. Then increase speed to medium-high and beat for another 2 minutes until light and fluffy. Set aside.