That also rings a bell. Many variations on this theme, all equally sick making. Treacle tart and custard was boss though.
In Kent we have Gypsy Tart (Ginger leave it!) and it is only at School and in Greggs. A bucket of sugar in every slice. I liked Jam roly poly though. Again never had it since.
You just reminded me of Lardy Cake, which I have onle ever come across in Southampton. Instant diabetes in every bite... please log in to view this image