Heads of turbot, tuna in leek stew requires water to come to the boil (6)
I believe the answer is:
kettle
'water to come to the boil' is the definition.
I can't tell whether this defines the answer.
'heads of turbot tuna in leek stew' is the wordplay.
'heads of' says to take the initial letters.
'in' means one lot of letters goes inside another.
'stew' indicates anagramming the letters.
The first letters of 'turbot tuna' is 'tt'.
'leek' anagrammed gives 'kele'.
'tt' placed inside 'kele' is 'KETTLE'.
'requires' is the link.
Can you help me to learn more?
(Other definitions for kettle that I've seen before include "Kitchen appliance" , "Water-boiler" , "The pot calls it black" , "Eurydice's husband" , "Kitchen utensil and type of drum" .)