One starts to make progress concerning such painting (7)
I believe the answer is:
impasto
'painting' is the definition.
(I have seen 'Thick painting ' mean 'impasto' so perhaps 'painting' could also mean 'impasto')
'one starts to make progress concerning' is the wordplay.
'one' becomes 'i' (Roman numeral).
'starts to' suggests taking the first letters.
'concerning' becomes 'asto' (I've seen this before).
The initial letters of 'make progress' is 'mp'.
'i'+'mp'+'asto'='IMPASTO'
'such' acts as a link.
(Other definitions for impasto that I've seen before include "Thickly-applied painting technique" , "Technique of paint applied thickly" , "Technique of applying paint thickly" , "Painting with pigment laid on thick" , "Thick-paint technique" .)