This recipe is very similar to what I make when I'm dying for chocolate.

I use unsweetened cocoa (about 1 Tbsp.), cream (an ounce or two) and Splenda (roughly a packet per ounce of cream)-- once I added cream cheese and butter to this and it tasted horrible -- the next time, I added another couple of packets of Splenda to it and a little less cream cheese, and it was wonderful.