Using a mixer, whip the heavy cream until soft peaks. Add ¼ cup powdered sugar and 1 teaspoon vanilla extract, and whip until stiff peaks form. Transfer it to a separate bowl and place it into the fridge until needed.
In a small bowl, whisk together the sweetened condensed milk, lime juice, and remaining teaspoon of vanilla extract until well incorporated.
In the same bowl (no need to rinse), whip the cream cheese and the remaining ¼ cup of powdered sugar until soft and fluffy.
Add the lime-infused sweetened condensed milk and lime zest into the cream cheese and whip until fluffy and incorporated.
With a spatula, carefully fold ¾ of the whipped cream into the cream cheese mixture.
Serve immediately or chill until ready to eat. Serve with graham cracker crumbs and the remaining whipped cream.
TIP: For the best flavor, cover the bowl with plastic wrap and allow the cream cheese fluff to set in the refrigerator for at least 2 hours.
STORE: Store lime cheesecake fluff for up to 3 days in the refrigerator. Be sure to store it in an airtight container and wait to garnish with whipped cream until service.
FREEZE: Freeze for up to 2 months. The texture will be different. It will be more like ice cream than mousse, but still equally delicious.