Summarize the following:
Place the yolks and the 6 tablespoons of sugar into a medium-sized metal mixing bowl. Whip them vigorously with a wire whisk until the mixture is pale yellow and fluffy. You may use an electric mixer instead. Put the 2 cups of milk and the vanilla bean into a small saucepan. Heat it over medium low heat until it's heated through to the point of scalding, but not boiling. Remove it from heat.  You can tell when the milk is scalded by watching the edges of the pan. When you see steam begin to rise where the milk touches the edge of the pan, it's time to remove it from heat. If you want a richer sauce, use 2 full cups of cream. For a less rich sauce, use only milk or one cup of milk and one cup of cream. Slowly pour the milk into the mixing bowl containing the sugar and egg mixture while whipping constantly with the wire whisk. Continue until the milk has been thoroughly blended with the sugar and egg mixture. Make sure the water in the bottom of the double boiler is simmering, and pour the egg, sugar and milk in the top part of the bain marie (or mixing bowl, if you made your own double boiler). Stir it constantly with a small rubber spatula. Do not let the sauce get too hot, as it can curdle. Keep stirring until the sauce is thick enough to coat the back of a metal spoon, then remove it from the heat.

Summary:
Whip the sugar and the egg yolks. Heat the milk with the vanilla bean. Stir the scalded milk into the egg mixture. Pour the sauce into the bain marie. Heat the sauce slowly.