Sweet eaten by Starmer in guesthouse (8)
I believe the answer is:
meringue
'sweet' is the definition.
(type of dessert or sweet)
'eaten by starmer in guesthouse' is the wordplay.
'eaten by' indicates the answer is hidden within the clue.
'MERINGUE' can be found hidden inside 'starmer in guesthouse'.
(Other definitions for meringue that I've seen before include "a really sweet item" , "Mixture of sugar and egg-white baked crisp" , "Dessert of beaten egg-white and sugar, baked crisp" , "Baked confection of beaten egg whites and sugar" , "Sweet cake" .)