Roses' Heavenly Cakes, Page 279: Hungarian Jancsi Torta.
The cake sank 1/2 inch in the centre but i wasn't alarmed as it was mentioned in the book that the cake will form 1/2-inch crater in the centre - perfect for filling. (i find that all flourless cakes sink in the centre when cooled). What i didn't particularly enjoy while baking this cake was to remove the skin from the walnuts after toasting. That took quite a while since i had difficulty rubbing off the skin from the walnuts! Otherwise, this is a pretty easy cake to bake and Rose's detailed instructions made it easier. :) I added 10g more sugar, since I only had 66-70% valrhona dark chocolate in my pantry.
I prefer the cake chilled since i find it a bit too wet for my liking when at room temperature. Anyone who loves walnut would definitely love this cake. My family, esp. my daughter enjoyed it, my husband said it is delicious and me? I find it nice, but not a huge fan as i don't quite like walnuts. I would probably have enjoyed it more if i'd substituted the walnuts with almonds or hazelnuts. Even for my dislike for walnuts, i did eat a huge slice, plain on its own without ganache. I like the light texture and the chocolatety taste to it..and actually the taste for the walnuts is not so overpowering with the presence of the chocolate imo.