Enthusiastically, dip tucked into early, but not starter (8)
I believe the answer is:
ardently
'enthusiastically' is the definition.
(both can mean passionately)
'dip tucked into early but not starter' is the wordplay.
'dip' becomes 'dent'.
'tucked into' means one lot of letters goes inside another.
'but not starter' means to remove the first letter.
'early' with its first letter removed is 'arly'.
'dent' put into 'arly' is 'ARDENTLY'.
(Other definitions for ardently that I've seen before include "full of enthusiasm?" , "with zeal" , "In a very passionate way" , "Passionately" , "With passion" .)