Green Tea Ice Cream

1 quart milk
..5 ounce powdered Japanese green tea
15 egg yolks
1 pound sugar
1 cup heavy cream
1 cup half & half
Bring milk to a boil. Remove from heat and add green tea. Mix well.
In a separate bowl, beat egg yolks and sugar together until they form
a ribbon. Combine egg mixture and milk, then strain into a saucepan.
Cook over medium-high heat until just before the mixture reaches a
boil. Remove from heat and cool completely over ice water. Beat
heavy cream and half & half until frothy. Pour into egg mixture and
mix well. Process in an ice cream maker according to manufacturer's
instructions.