There's a great little Japanese grocery in DC called Hana Market (2005 17th St., NW, on the corner of 17th and U). It's the only place in the city where I have been able to sushi grade fish and other Japanese specialty products. On a recent trip, I asked the owner, a very friendly old Japanese man, if he had any green tea powder that I could use to make ice cream. He found only one tiny jar that was very expensive on the shelf. Instead, he went in the back, poured a few spoonfuls (enough for several batches) of his own green tea powder into a little baggy and gave it to me. I love this man.
If you can't find green tea powder in the store, there are many varieties available online:
The powder gives the ice cream a much more concentrated flavor than steeping tea leaves in the milk. Plus, it's faster!
I added the powder after creating the custard. If it clumps, use a blender or electric mixer to smooth it out.
1 1/2 cups whole milk
1 1/2 cups heavy cream
3/4 cup sugar
5 egg yolks
2 teaspoons green tea powder.
Combine milk, cream, and sugar in a saucepan over medium heat. Stir to dissolve the sugar. In a separate bowl, whip egg yolks. Just before the milk begins to simmer, add about half the mixture to the bowl of egg yolks half a cup at a time, stirring constantly. Slowly pour the egg yolk mixture back into the saucepan, stirring constantly. Keep stirring until a thick custard forms, coating the back of a spoon. Remove from heat. Stir in green tea powder. Chill using an ice bath or refrigeration. When cold, add ice cream mix into ice maker and churn.