Preparation / Directions:
In a large heavy saucepan, combine the milk, heavy cream, vanilla beans and sugar. Heat on low until the mixture begins to steam (half an hour).
Place beaten egg yolks in a medium bowl. Whisk in a bit of the hot milk mixture. Stir egg/milk mixture back into large saucepan. Continue cooking over low heat, stirring constantly until mixture forms a thin custard (5-15 minutes). Remove pan from heat. Scrape the black vanilla seeds inside vanilla beans and mix into custard. Throw away empty vanilla pods. let the custard cool for 15 minutes.
Fit a food processor with a metal blade. Put diced marzipan into food processor. Add one sixth of the warm custard mixture and pulse until the marzipan softens (4-5 times). Add another one sixth and blend until smooth (one minute). Pour marzipan custard mixture into plain custard mixture. Mix well.
Pour the mixture into a large pan, or two medium sized pans (like two 9 x 5 x3 loaf pans) and freeze the mixture until it is mushy. This will take at least 4 hours, because of the richness of the ice cream. Empty the ice cream mixture into a large electric mixer bowl, and beat 2 minutes at the highest speed, until fluffy, Pack into a 1/2 gallon plastic freezer container and freeze until semi firm.