Would add in Vanilla Bourbon - aka Bourbon @ 0.2% to get a vanilla note without adding creams, plus will give it a more soft grain feel, or just vanilla (flavrz) though at 0.1-0.2% if you are chasing on in the base. Also Marshmallow (Flavrz) will add to the puff pastry here as well @ 1% odd… though again depends what you are looking for. This is more a Puff Pastry base above.
The options are endless as you could add cookie dough (Flavrz) instead of the sponge cake, cookies & cream (flavrz) , Golden Syrup (flavrz) , golden butter (flavrz) to spin it a different way.