Trim each japonais layer to a perfect 8-in/20cm round. Slice one layer from the chiffon sponge, between ¼ and ½ in/0.6 cm and 1 cm thick.
Blend the hazelnut liqueur and honey into the diplomat cream.
Smear a dollop of the diplomat cream onto the center of an 8-in/20-cm cardboard cake round and place one of the japonais rounds on top. Coat with 5 oz/14