### Clue: It would make Angus flip to take in recipe by first-class cook (6)
### Answer: BRAISE 
 ### Explanation: Definition: cook
  BSE($$b$$ovine $$s$$pongiform $$e$$ncephalopathy,mad cow disease, that would make eg. Aberdeen Angus, a breed of cattle, go mad,flip) **containing**(to take in) R(abbrev. for recipe, as used in medical prescriptions) **plus**(by) AI(looks like A1,first class)