Hot pill formula at the summit (7)
I believe the answer is:
hilltop
'the summit' is the definition.
(hilltop is a kind of summit)
'hot pill formula' is the wordplay.
'formula' indicates anagramming the letters (the letters are the ingredients or formula).
'hot'+'pill'='hotpill'
'hotpill' anagrammed gives 'HILLTOP'.
'at' is the link.
(Other definitions for hilltop that I've seen before include "Peak of an incline" , "watershed?" , "Brow of mound" , "Crest or crown of an upland area" , "Prominent place" .)