Almost beyond heartless nut (6)
I believe the answer is:
'nut' is the definition.
(almond is a kind of nut)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for almond that I've seen before include "Kind of nut, makes nice icing on cake", "Nut which provides cake icing", "Nut used in marzipan", "Fruit kernel of a peach-related tree", "Nut often used in cake icing (6).".)