Tarta de Santiago is a traditional almond cake from the region of Galicia in Spain, but it can be found in many bakeries and restaurants in Madrid. The cake is made with ground almonds, sugar, eggs, and lemon zest, resulting in a moist and flavorful dessert. Tarta de Santiago is often dusted with powdered sugar and decorated with the cross of Saint James. It is a delicious and gluten-free option for those with dietary restrictions.