At least one hour prior to making rice pudding, soak the raisins in the vanilla. A longer soak of over 24 hours is optimal.
In a medium-sized, heavy-bottomed saucepan, bring the milk, heavy cream, uncooked rice, and salt to a boil over high heat. As soon as it starts to simmer around the edge of the pan, reduce heat to the lowest temperature where you can maintain a simmer, partially covered, until the rice is tender, about 20-25 minutes. Stir frequently to prevent the rice from sticking to the bottom of the pan. Taste the rice to ensure it is done. You want it tender but still firm.
In a separate bowl, whisk together eggs and sugar. Add a ladel of the hot milk mixture to the egg mixture, whisking while pouring it in a very slow steady stream. Your goal is to bring the temperature of the egg up without curdling the egg.
Continue to add more of the hot milk mixture to the egg mixture, whisking continually, until the egg mixture is warm.
Add tempered egg mixture back into the saucepan of rice and milk and stir over low heat for 5 to 10 minutes, until thickened. This rice pudding can go from thin to too thick rather quickly, so don't leave it unattended. Also keep in mind that it will thicken even more as it cools. A temperature of 160°F will ensure the eggs are cooked all the way through.
When done, remove from heat and stir in the pumpkin pie spice and soaked raisins.
Serve warm or cold.