That's exactly the recipe I used.

The batter cooked too slowly and hence absorbed too much oil.

The sandwich was good, but I'm not satisfied with just "good".
I might try 50% rice flour or tapioca flour in the batter to see if I can make it crispier.

Maybe my fryer has problems and isn't getting hot enough or re-heating fast enough after food is put into it.

Good coffee, good weed, and time on my hands...