Cake provided by entrance to a university (6)
I believe the answer is:
gateau
'cake' is the definition.
(gateau is a kind of cake)
'by entrance to a university' is the wordplay.
'by' means one lot of letters go next to another.
'entrance' becomes 'gate' (I've seen this before).
'university' becomes 'u'.
'gate' next to 'a' is 'gatea'.
'gatea'+'u'='GATEAU'
'provided' is the link.
(Other definitions for gateau that I've seen before include "Cake for Pierre" , "Afternoon snack" , "Cream dessert cake" , "Cake (from the Black Forest?)" , "It's sweet" .)