Ice cream base

600 ml cream
1 tin sweetened condensed milk

Whip the cream till thick then mix in the condensed milk. Add flavourings and freeze …

Flavourings

Liqueurs and nuts (e.g. Kahlúa and macadamias, or Baileys and walnuts … or anything you like)
Fruit (fresh or defrosted berries work well, as does dried fruit and nuts soaked in brandy)
Japanese green tea powder
Whatever you like, really ...

If you want to make the green tea variant, make sure you get matcha green tea powder. This is sold in tiny tins in Asian grocery shops; it is quite expensive but goes a long way. Just mix about a tablespoon of green tea powder with boiling water, cool, then mix this into the ice cream base, and freeze. (You can also use the green tea powder to flavour other stuff like crème brulée, or to make any pale-coloured dessert a pretty green colour ;-)