In a large pot, over high heat, bring 2 cups of water to a boil. Add the salt and then rice. Reduce heat to low. Cover and simmer for between 15 and 20 minutes. You have to stir the rice regularly until the rice is cooked and the water is almost totally absorbed into the rice.
Now add the cream first. Then the milk and then the sugar. Stir until blended. Turn your heat up to medium high and bring it to a simmer. Once simmering, reduce your heat to medium low and simmer, uncovered for between 35 and 45 minutes. You must stir this regularly, especially as it thickens.
As the rice mixture gets really thick, add cinnamon if you are using it. I recommend adding ½ a teaspoon first. Stir until combined. After a few minutes taste it and decide if you would prefer a little more cinnamon. Reduce the temperature to low and stir frequently so the rice pudding doesn't stick to the bottom of your pot. Keep on stirring over low heat until a little spoon is able to stand up on its own, another 10-15 minutes.
Once your pudding is thick enough remove it from heat. Add the vanilla and stir. Next, add as many raisins and slivered almonds as you would like. I have given you a rough idea of how much I use. Add some of each and stir until you are satisfied with how much you have added! If you are going to use a couple of whole almonds for everyone to search for this is the time to do it. If you have three prizes, my grandmother used to have them sitting on the table beside her for whoever found the 3 whole almonds!
Allow rice pudding to cool before serving. You can serve it at room temperature but I always serve it cool. You can store this pudding in a sealed container in your refrigerator for a couple days.