cup of tea

cup of tea also dish of tea  {n. phr.},  {informal}

1. Something you enjoy or do well at; a special interest, or favorite occupation. Used with a possessive.

You could always get him to go for a walk: hiking was just his cup of tea.

Compare: DOWN ONE'S ALLEY.

2. Something to think about; thing; matter.

That's another cup of tea.

Compare: KETTLE OF FISH.