Prepare the pan: coat the inside of a 9 inch springform pan with butter. Dust with flour, covering bottom and sides. Shake off the excess.
In a large mixing bowl, add the eggs, lemon zest, cinnamon and sugar and mix well. Add the ground almonds and mix. Add the almond flour and mix well until fully incorporated.
Pour batter in prepared pan and bake for 25 minutes or until golden brown (check after 20 minutes to avoid over baking).
Let the cake rest over a cake rack until completely cooled down. Place the stenciled cross of Saint James in the center of the cake and dust freely and generously (yes, over dust!) with a thick layer of icing sugar. Make sure not to leave any surface uncovered.
With the tip of a knife, carefully lift the stencil.
Notes
It’s easy to find a stencil of the cross of Saint James in Spain, not so easy in the United States. I googled it, printed it, and carefully cut it out with a paper cutter (I’m saving it for future cakes!)