Pray there's melted cheese on first of burgers (7)
I believe the answer is:
beseech
'pray' is the definition.
(thesaurus)
'melted cheese on first of burgers' is the wordplay.
'melted' is an anagram indicator.
'on' says to put letters next to each other.
'first of' says to take the initial letters.
The initial letter of 'burgers' is 'b'.
'cheese' is an anagram of 'eseech'.
'eseech' after 'b' is 'BESEECH'.
'there's' is the link.
(Other definitions for beseech that I've seen before include "Sue" , "Entreat, implore" , "request, urgently" , "wood" , "pray" .)