1. Preheat your oven to 180°C (350°F). line a 9-inch (22-23cm) springform pan with parchment on the bottom and rub the bottom and sides with butter.
2. In a large bowl place eggs, lemon zest and sugar. Whisk until light and pale, about 3-4 minutes.
3. Add ground almonds, salt, cinnamon and mix until combined and smooth.
4. Pour the batter into the prepared cake pan and place in the preheated oven. Bake for approximately 35-40 minutes or until a skewer inserted in the middle comes out clean.
5. Meanwhile, make the cross stencil, I will add a printable version on my website.
6. Let the cake cool in the pan on a wire rack for about 10 minutes. Remove it from the pan and let it cool completely on the wire rack.
7. Once cooled, dust the top of the cake generously with powdered sugar. To create the traditional Tarta de Santiago look, you can place a cut-out of the Santiago cross in the center of the cake before dusting with powdered sugar, then carefully remove the template to reveal the design.