Rick Stein's beginning to get into dope (5)
I believe the answer is:
twist
'rick' is the definition.
(I know that rick can be written as twist)
'stein's beginning to get into dope' is the wordplay.
'beginning to' indicates taking the first letters.
'get into' means one lot of letters goes inside another.
'dope' becomes 'twit' (both can mean a stupid person).
The first letter of 'steins' is 's'.
's' inserted into 'twit' is 'TWIST'.
(Other definitions for twist that I've seen before include "Change - 1960s' dance" , "Rotate rapidly" , "Torsion" , "Form into a distorted shape" , "Wind about; sixties dance" .)