For the matcha parfait, first whip the sugar and egg yolks over a water bath until creamy.
Stir the matcha powder into the warm milk. Stir the mixture into the egg yolk-sugar mixture and allow to cool slightly.
Whip the cream until stiff and stir it in as well. Line a terrine mold (or several or another suitable container) with plastic wrap and pour in the parfait mixture.
Place in the freezer for several hours, preferably overnight, until the matcha parfait is firm.