Modern coffee bar daughter opens (6-3)
I believe the answer is:
latter-day
'modern' is the definition.
(I've seen this before)
'coffee bar daughter opens' is the wordplay.
'coffee' becomes 'latte' (I've seen this before**).
'bar' becomes 'ray' (both can mean a line of something, eg of light).
'daughter' becomes 'd'.
'opens' means one lot of letters goes inside another (one set of letters makes an 'opening' in another).
'ray' going around 'd' is 'rday'.
'latte'+'rday'='LATTER-DAY'
(Other definitions for latter-day that I've seen before include "Contemporary" , "Mormons belong to The Church of the . . . . . .-. . . Saints" , "Belonging to recent times" , "Modern" , "Church of Jesus Christ of ... Saints" .)