Crunchy-Topped Almond Cake

Ingredients

• 1 large egg white
• 1½ cups (150 g) sliced almonds, blanched or unblanched
• 1¾ cups (238 g) all-purpose flour
• 1¾ teaspoons baking powder
• ½ teaspoon fine sea salt
• ½ teaspoon baking soda
• ¼ teaspoon freshly grated nutmeg
• ¾ cup (75 g) almond flour
• 2 large egg whites, at room temperature
• 1 large egg, at room temperature
• 1 cup (200 g) granulated sugar
• ¾ cup (150 g) light brown sugar
• 12 tablespoons (170 g) unsalted butter, at room temperature
• ¼ cup (60 ml) neutral oil
• 2 teaspoons pure vanilla extract
• ½ teaspoon pure almond extract
• 1 cup (240 ml) full-fat buttermilk, well shaken and at room temperature
• A couple pinches fleur de sel or flaky sea salt, for finishing
• Sanding sugar, for finishing

Instructions

1. Center a rack in the oven and preheat to 350°F (175°C). Coat a 9-by-13-inch baking pan, at least 2 inches deep, with baker’s spray, or butter and flour it. Line the bottom and two long sides with parchment, leaving an overhang.
2. Make the topping: Lightly beat the single egg white in a medium bowl just to break it up. Add the sliced almonds and toss with your fingers for 1 to 2 minutes, until every almond is lightly coated. Set aside.
3. Whisk the all-purpose flour, baking powder, salt, baking soda, and nutmeg together in a medium bowl. Whisk in the almond flour, breaking up any lumps.
4. In a small bowl, lightly whisk the 2 egg whites and whole egg together just until combined.
5. Beat the granulated sugar, brown sugar, and butter with a stand mixer fitted with the paddle, or with a hand mixer, on medium speed for about 3 minutes, until creamy and light. Scrape the bowl and beaters often.
6. With the mixer on medium-low, slowly pour in the oil and beat for 2 minutes. Reduce the speed to low and gradually add the egg mixture; increase to medium and beat until smooth and airy. Mix in the vanilla and almond extracts.
7. On low speed, add one-third of the flour mixture, followed by half of the buttermilk. Repeat, then add the final third of the flour. Mix only until the dry ingredients disappear; finish folding by hand so the batter stays tender.
8. Spread the batter evenly in the prepared pan. Scatter the coated almonds over the entire surface, separating any large clumps. Sprinkle generously with sanding sugar and finish with a couple pinches of flaky salt.
9. Bake for 38 to 45 minutes, rotating the pan after about 25 minutes, until the top is deeply golden and crunchy and a tester inserted in the center comes out clean. If the almonds brown too quickly, tent the cake loosely with foil.
10. Cool in the pan for 20 minutes, then use the parchment to lift the cake onto a rack. Cool completely before cutting into 12 squares.