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.
Categories: 
 
Source: A Dictionary of American Idioms

