… leaving spiritualism to go off for some pudding (8)
I believe the answer is:
tiramisu
'pudding' is the definition.
(type of dessert or pudding)
I cannot understand how the rest of the clue works.
(Other definitions for tiramisu that I've seen before include "Arenaceous material" , "Rich Italian dessert" , "Dessert soaked in alcohol" , "for which damp sponge is needed" , "Dessert (Italian "pick me up")" .)