I gave up lupin flour to see if it might help my arthritis, not sure it did, but I had an opportunity to try this recipe with other flours and meals:

Almond meal: Works great, be careful not to over cook. I used 1/4 cup.
Cashew meal: Worked really well. I picked up some of this in Trader Joe's. I'm sure the processors must get rid of cashew pieces that are too small to sell that way.

Since I don't use frosting any longer, I top with a sprinkle of cinnamon and a couple of spoonfuls of brown non-caloric sweetener (like Ideal Brown).