Strawberry Ice Cream
Cut vanilla beans lengthwise and scrape out seeds. Combine milk with vanilla beans and seeds and bring to a boil. Remove pan from heat and let stand for about 30 minutes.
Beat egg yolks with sugar and vanilla sugar until fluffy.
Remove vanilla beans from milk. Combine still warm milk (reheat if necessary) with egg mixture, stirring constantly. Heat milk and cook until it just comes to a boiling point. Add lemon zest, mix well and remove from heat. Cool, stirring occasionally. Place in a freezer for approximately 3 hours and stir every half an hour.
Rinse, dry and hull strawberries. Combine with powdered sugar and puree. Pour into a shallow dish and freeze for 3 hours, stirring every half an hour.
When vanilla ice cream and strawberry puree are frozen but still spreadable and soft, mix to create a marbled effect. It might be necessary to defrost both until it becomes possible to mix them. Place marbled ice in a bowl and freeze for one more hour. Thaw shortly before serving. Scoop and serve immediately.