Cooler, with start of frost on hilltop (6)
I believe the answer is:
fridge
'cooler' is the definition.
(refrigerator)
'start of frost on hilltop' is the wordplay.
'start of' says to take the initial letters.
'on' is a charade indicator (letters next to each other).
'hilltop' becomes 'ridge' (I've seen this before).
The first letter of 'frost' is 'f'.
'f'+'ridge'='FRIDGE'
'with' is the link.
(Other definitions for fridge that I've seen before include "A domestic appliance" , "Food cooler" , "Cooler in kitchen" , "Cooling cabinet (abbr)" .)