From Nigella Lawsons new book Nigellissima . It's is also gluten free as it uses ground almonds and I used gluten free bicarbonate of soda . A soft squishy interior a bit like a brownie . Divine .
Yes, ground hazelnuts. I'm trying to remember what cookbook I found it in. It was called Hazelnut Torta, so it may have been a Mexican cookbook. Seeing your cake reminded me of it.
I think you could use any ground nut, depending on the flavor profile you want. We need to brainstorm a Pineapple Upside Down Cake made with ground Macadamias.