Root of resistance to a recipe (6)
I believe the answer is:
radish
'root' is the definition.
(radish is a kind of root)
'of resistance to a recipe' is the wordplay.
'of' indicates anagramming the letters (the answer comes from or 'of' the letters).
'resistance' becomes 'r' (electronics abbreviation).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'recipe' becomes 'dish'.
'r' after 'a' is 'ar'.
'ar' anagrammed gives 'ra'.
'ra'+'dish'='RADISH'
(Other definitions for radish that I've seen before include "Plant with crisp root eaten raw" , "Hard vegetable" , "Sir had this vegetable" , "Hottish salad plant" , "Pungent, red salad vegetable" .)