I was given prune and walnut slice; I thought it was a very good idea for a healthy snack. I had some walnuts and prunes and a pretty good idea of how to go about reproducing the texture and taste of this delicacy. I must add that at the time I had no idea who made it or where it came from. After I made my own I looked up the recipe on the internet and I saw a picture of a walnut log and found out where it came from and then saw your question and I decided to share my recipe with you
Well here’s my recipe
500gr pitted prunes
400gr chopped walnuts (this can be blanched, I use them with skin)
Place and process the prunes in a food processor until they are mushy, remove the prunes and place them on grease proof paper. Spread the pure to make a square. Spread the walnuts along the edge of the square about an inch wide and roll the mushy prunes tie continue in this manner until you have a roll. Make sure you roll fairly tie, stand the roll on end and press it down and reshape again by rolling it back and forth. At this point you can cut the roll in half. Let the roll stand for half an hour and bake in a very low oven for half an hour, make sure the roll/s stand on end do not lie them down. Turn oven off and let the roll/s cool down in the oven. Store them in a glass air tie container. I cannot tell you how long it would keep.
Well I hope you get to see this answer to your question. Sincerely Myrna Mack