A European upset about most of pepper in Mexican dish (9)
I believe the answer is:
enchilada
'mexican dish' is the definition.
(I've seen this before)
'a european upset about most of pepper' is the wordplay.
'european' becomes 'dane' (Dane is an example**).
'upset' shows that the letters should be reversed in order.
'about' indicates putting letters inside.
'most of' means to remove the last letter.
'pepper' becomes 'chili' (chili is a kind of pepper).
'a'+'dane'='adane'
'adane' reversed gives 'enada'.
'chili' with its last letter taken away is 'chil'.
'enada' placed around 'chil' is 'ENCHILADA'.
'in' is the link.
(Other definitions for enchilada that I've seen before include "spicy snack" , "spicy food" , "The whole ___ -- everything (US)" , "Tortilla and sauce, meat" , "Tortilla with meat and chilli" .)