It's very easy to make your own whipped cream:

Heavy whipping cream
Artificial sweetener (I use Splenda)

Mix these together with a handmixer until the consistency you desire. It's a good idea to put the beaters and the bowl in the freezer ahead of time to make it very cold. The cream whips up better and quicker!

I don't think you need to add anything else (I'm doing it from memory) but I'm sure someone will correct me.

Regards,
Stephanie