Cookie ___ (3)
'cookie' is the definition.
(synonyms)
This is all the clue.
(Other definitions for biscuit that I've seen before include "Eg, custard cream" , "Light brown colour" , "award for a most remarkable recipient?" , "Rich tea, for example" , "Eg, ginger nut" .)
(Other definitions for jar that I've seen before include "Grate" , "Glass of beer; clash" , "drink" , "Vessel; sudden impact" , "(Jam) pot" .)