Leaders in game are unusually full of tea and cake (6)
I believe the answer is:
gateau
'cake' is the definition.
(I know that gateau is a type of cake)
'leaders in game are unusually full of tea' is the wordplay.
'leaders in' indicates taking the first letters.
'full of' indicates putting letters inside.
The initial letters of 'game are unusually' is 'gau'.
'gau' going around 'tea' is 'GATEAU'.
'and' is the link.
(Other definitions for gateau that I've seen before include "Richly decorated cake" , "Cream dessert cake" , "Rich cream cake" , "named for Black Forest?" , "Gooey cake" .)