Making a cake without wheat flour or any chemical leavening agents may seem like a recipe for a dense, overly moist disaster, but the Spanish tarta de Santiago is tender, light and almost springy, with a chewy crust that contrasts beautifully with a just-moist-enough interior. It’s also one of our most popular cakes, and one of the stars of our cookbook “Milk Street Bakes.”

One would expect to find a secret molecular ingredient in the recipe, or at least the use of a stand mixer, but none of that is in play with this cake. It’s just sugar, finely ground almonds, eggs and a couple of extracts, mixed in one bowl and baked in a standard cake pan. The secret to this cake’s success? A few extra egg whites.

Don’t separate—supplement

When we first set out to replicate the tarta we tasted in Sanitiago, we followed cookbook author Claudia Roden’s recipe from her book “The Food of Spain.” She separates the eggs, beating the yolks with sugar, almond flour and flavorings, then whips the whites before mixing them into the almond-yolk mixture. Great in theory, but whipped egg whites and yolky ground almonds have very different consistencies. Folding the two together, no matter how gently, knocked much of the air out of the whites, resulting in a cake that was a bit dense for our liking.

Rather than separating our eggs, we decided to supplement. By adding a few extra whites to a mixture of whole eggs, almond flour, sugar and almond and vanilla extracts, we increased the volume of air we could incorporate into the batter, without worrying about knocking it out later. This method produced a tender, springy cake every time, and it kept it down to a one-bowl affair.

A sprinkling of turbinado sugar creates a chewy-crunchy crust

Turbinado sugar is minimally processed, with a large crystal size and an amber hue from the natural molasses found in sugar cane. It can be difficult to bake with—larger crystals take longer to dissolve—but it makes a gorgeous sparkling crust. For this cake, we combine chopped slivered almonds with 3 tablespoons of the sugar to create a crust that crunches before giving way to the soft, plush crumb underneath.

Unlike other cakes, we don’t use a toothpick to tell when this one is done. Just keep an eye on that crust. Once it’s deeply browned and feels firm to the touch, the cake is ready to come out of the oven. Be sure to let it cool completely before serving—neither the exterior nor interior will have the proper texture if served warm.

Finish with restraint

This cake was so easy to make, I felt like I was forgetting something. But I wasn’t. It really takes all of an hour, with only 10 minutes of active time, and you don’t even need a frosting. But if you simply must gild the lily, we recommend a dollop of subtly tart crème fraîche and fresh berries as the perfect accompaniments.

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Claire Lower

Claire Lower is the Digital Editor for Christopher Kimball’s Milk Street, with over a decade of experience as a food writer and recipe developer. Claire began writing about food (and drinks) during the blogging boom in the late 2000s, eventually leaving her job as a lab technician to pursue writing full-time. After freelancing for publications such as Serious Eats, Yahoo Food, xoJane and Cherry Bombe Magazine, she eventually landed at Lifehacker, where she served as the Senior Food Editor for nearly eight years. Claire lives in Portland, Oregon with a very friendly dog and very mean cat. When not in the kitchen (or at her laptop), you can find her deadlifting at the gym, fly fishing or trying to master figure drawing at her local art studio.