Too much nutmeg. Way too much nutmeg. I figured this would probably be the case and cut down the amount a bit -- but nowhere near enough.
1/2 cup whipped cream
1 cup fat-free half and half
1/2 cup nonfat milk
3/4 teaspoon nutmeg
1 teaspoon cinamon
Even with the whipped cream I'm still getting a lot of ice crystals. Not sure how to take care of that. We'll see how it is after the whole thing has solidified.
Next experiment: Mexican hot chocolate. I'm making up the mix right now.