Round child tucked in to cheese roll (7)
I believe the answer is:
brioche
'roll' is the definition.
(I know that brioche is a type of roll)
'round child tucked in to cheese' is the wordplay.
'round' becomes 'o' (o is a circular letter).
'child' becomes 'ch' (abbreviation for child).
'tucked in to' is an insertion indicator.
'cheese' becomes 'brie' (Brie is an example).
'o'+'ch'='och'
'och' going inside 'brie' is 'BRIOCHE'.
(Other definitions for brioche that I've seen before include "Sweet yeast bread" , "Soft roll made of light yeast dough" , "Hire cob (anag) - bread" , "Light cake-like loaf or roll" , "Small French roll" .)