Rich Rice Pudding

1/2 cup raw medium-grain rice
3 cups milk
2 cups cream
1 cup granulated sugar
1 vanilla bean
1/2 cup dark raisins
3 egg yolks
2 tablespoons unsalted butter

Add rice to boiling water and blanch 5 minutes. Drain, then return to pan and add milk, cream and sugar. Add vanilla bean, which has been split, scraped and added to the rice