In a medium saucepan, bring the Manischewitz to a boil with the cinnamon sticks. Reduce to a simmer and simmer until it is reduced to 1 cup, about 30-40 minutes.
Meanwhile. in a metal bowl, beat the egg yolks until they lighten in color. Set aside.
In a separate large saucepan, combine the cream, milk, sugar and vanilla and bring to a boil and then turn off the heat. Temper hot liquid into the egg yolks by adding a little at a time and mixing as to not cook the eggs. Return the whole mixture to the cream saucepan and cook over medium heat until the custard is thick, about 10 minutes. Make sure not to let the mixture boil or it will curdle.
Strain the custard into a bowl and stir in the reduced Manischewitz.
Cover and freeze for 30 minutes up to overnight until chilled. Then freeze in your ice cream maker according to the directions and then freeze at least two hours until ready to serve.