In a medium saucepan, bring cream, half and half, vanilla and salt to a low simmer. Keep the heat on low and watch the mixture to avoid boiling.
While the liquid is heating up, add butter to a dutch oven. Once the butter has melted, add the rice and stir. Allow it to toast for a few minutes, stirring, then add red wine to deglaze the pan.
Once the wine has cooked into the risotto and not a lot of liquid remains in the pan, add a ladle of cream. Stir frequently, allowing the cream to slowly absorb into the rice. Adjust the temperature as needed, alternating between low and medium low. You don't want to the heat too high or the liquid will be gone before the risotto is fully cooked. Keep an eye on the saucepan with the cream as well. You want it barely simmering to prevent reducing.
Repeat the process of adding cream and stirring until all of the liquid has been used, approximately 30 minutes. Test the risotto for doneness. It should be soft but slightly toothsome. If necessary, continue cooking and stirring on low heat until the rice has finished cooking.
Stir in the chocolate and remove the pan from the heat. Continue stirring until the chocolate is fully incorporated.
The risotto will thicken as it sits. Stir in additional half and half if desired to create a thinner consistency (start with 1/2 cup). Garnish with toasted sliced almonds before serving.
Notes
Tip: if you run out of liquid but feel the rice still has a long way to go, you can heat up some more half and half and continue ladling it into the rice.