At the casa mora bakery in Santiago de Compostela, Spain, a forkful of springy, fragrant almond cake taught us a history lesson — and an easier method for lightening flourless cakes.
Ultra-moist from almond flour and dense from a lack of leavener, the tarta de Santiago is named after St. James the Apostle, whose remains are believed to be entombed in the city's cathedral. The flourless cake has been popular for centuries, but it particularly boomed after 1924, when Casa Mora began marking theirs with powdered sugar in the shape of the cross of the Order of Santiago. What was once just known as a Galician almond cake gained a name and eventually a reputation that spread throughout Spain. (A downloadable stencil of the cross often accompanies recipes on Spanish cooking websites.)
Beyond its clever marketing, tarta de Santiago has a rich texture and a nuanced flavor from a bit of cinnamon and lemon zest. The formula for the cake is easy: equal parts white sugar and finely ground almonds, plus half a dozen whole eggs (or more). Though there's no leavener in traditional recipes, bakers incorporate air by vigorously beating the eggs.
At Milk Street, we loved the cake's simplicity and its reliance on almond flour. We were skeptical, however, that whisking whole eggs would be enough to build lightness into the cake.
So at first, we followed cookbook author Claudia Roden's lead. In her recipe for tarta de Santiago in The Food of Spain, she separates the eggs — first beating the yolks with sugar, followed by citrus zest, almond extract, and finely ground almonds. She then thoroughly whips the whites before mixing them into the almond-yolk mixture.
But because the yolk and almond base was extremely thick and pasty — a consistency that was very different from the beaten whites — no matter how careful we were when combining the two, they proved difficult to mix without knocking much of the air out of the whipped whites. This resulted in a cake that was a little too dense and heavy.
To our surprise, we found an easy fix for this problem by making a slight tweak on tradition — vigorously beating whole eggs with sugar, but adding extra egg whites. Whisking together three whole eggs plus three whites and then incorporating the almond flour lightened the batter and produced a chewy, deliciously springy cake every time.
The reason our new method worked so consistently is that the added egg whites increased the amount of air we could beat into the egg-and-sugar base. And because we weren't folding whipped egg whites — notoriously unstable, even when treated carefully — into a dense mixture of egg yolks and almond flour, we avoided the difficulty of combining two mixtures with different consistencies. An added bonus: We didn't need to dirty a second bowl.
With our one-bowl mixing method resolved, we fine-tuned the flavors. We skipped citrus zest and cinnamon in favor of almond and vanilla extracts. The almond reinforced the nuttiness of the almond flour, and vanilla balanced the flavor of the eggs.
Once we had fully incorporated the almond flour into our almond- and vanilla-laced batter, we poured it into a parchment-lined cake pan. We sprinkled the top with chopped almonds and a bit of turbinado sugar. As the cake baked, the nuts and sugar formed a chewy-crisp crust that gave the final product a lovely textural contrast and visual flair, rendering any powdered sugar — or a stencil — unnecessary.
For the recipe and more, visit Christopher Kimball's Milk Street.