The key to this ice cream is patience. Custard style ice creams use eggs to add richness, and must be cooked very gently to prevent clumping. Place all the ingredients in a medium saucepan and heat slowly over medium low heat, stirring constantly, until it begins to thicken. How thick? It will begin to resist the spoon, but still be very liquid. Imagine mixing heavy latex paint-- it should be that thick. Scrape down the sides and bottom as you stir. If you fail to keep the mixture circulating, it will cook unevenly and you'll end up with bits of scrambled egg!
Heat saucepan and add milk, slowly bringing it to a boil. Once boiling, add tea leaves and place cover on pan. Let set for 15 minutes. In a bowl beat egg yolk and sugar. Add cornstarch. After the 15 minutes, remove pan from heat and strain mixture to remove the tea leaves. Place milk in bowl and add the egg, sugar and cornstarch mixture.
Whisk contstantly, not allowing eggs to become to hot. Whisk until custard forms and is slightly thick. Remove pan from heat and once again strain the ingredients, placing the mixture into a new clean bowl. Set aside to cool, and then add cream. Place in container and freeze.
The easiest way to make green tea ice cream is to mix vanilla ice cream and maccha powder. Also, it's good to pour maccha sauce over vanilla ice cream.
In a large bowl beat the egg yolks with the sugar and salt. Set aside. In a heavy saucepan, scald the milk. Remove from the heat. Add the tea, cover and steep for 4 minutes. Strain through a fine mesh sieve into a clean pot, pressing with a rubber spatula to extract as much liquid as possible. Add heavy cream and bring to a simmer over medium-high heat. Ladle 1/3 of the cream mixture into the eggs and whisk well to combine. Add all the egg mixture to the pot and cook over low heat, stirring, until thick enough to coat the back of a spoon, about 5 minutes. Strain through a fine mesh sieve into a clean container and cool in the refrigerator, about 2 hours.
Whisk together eggs, sugar, and match in a bowl then add 1 cup hot cream mixture in a slow stream, whisking vigorously. Whisk custard into remaining cream mixture in saucepan and cook over moderately low heat, stirring constantly with a wooden spoon, until thick enough to coat back of spoon and registers 170°F on an instant-read thermometer.
Heat the milk/cream/sugar/egg mixture over low heat until it coats the back of a spoon - most of the other recipes. This step which gives a little peace of mind about ensuring the eggs are cooked strain that mixture through a fine sieve before adding in the lightly whipped cream to make sure it's perfectly smooth.
Heat milk with tea for 5 minutes just below a simmer. Whisk together egg yolks and sugar. Gradually whisk hot milk into egg mixture until all milk has been added. Return to pot and cook over medium-low heat, stirring with a wooden spoon until it coats the back of a spoon. Strain and chill completely. Stir in cream and green tea powder and churn in an ice cream maker according to manufacturer's instructions. Spoon into a container and freeze until firm.
Put the sugar in the small pan and melt them with medium heat. After sugar turns to be golden brown, add boiling water and heat carefully without stirring sugar. After the sugar is completely melted and becomes soft, take it off the burner. Pour the caramel sauce into the cups while it is hot.
