What's often put on the fork is ostentatiously sumptuous (5)
I believe the answer is:
ritzy
'sumptuous' is the definition.
(I've seen this in another clue)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for ritzy that I've seen before include "Ostentatiously rich" , "Ostentatiously stylish" , "Luxurious" , "Expensively stylish" , "Richly elegant" .)