½teaspoonxanthan gumomit if your blend already contains it
⅔cup(5.333fluid ounces)buttermilkat room temperature
¼cup(36g)36 g cornstarch
1 ½teaspoonsbaking powder
2teaspoonsfreshly grated lemon zestfrom 1 large lemon
Fresh whipped cream and berriesfor serving (optional)
Preheat your oven to 350°F. Grease and line an 8-inch round pan, and set it aside.
In a large mixing bowl, place the sugar and olive oil. Using a handheld mixer, beat the mixture together until creamy (about 1 minute).
Add the eggs, vanilla extract, and salt, and beat until lighter in color and the mixture falls off the beater in ribbons (at least 2 minutes more).
Into the large mixing bowl, sift the flour blend and xanthan gum and beat until just combined.
Add the buttermilk, and beat again until just combined.
Sift in the cornstarch, baking soda, and baking powder into the large mixing bowl, and beat again to combine.
Add the lemon zest and mix to combine, breaking up any lumps in the zest. Be sure to scrape down and mix in any unincorporated flours on the side of the mixing bowl. The batter should be thickly pourable and pale yellow in color.
Transfer the batter to the prepared pan. Spread into an even layer with a moistened silicone or offset spatula.
Sprinkle the top of the cake lightly with about another 1 1/2 tablespoons granulated sugar in an even layer. This step is optional.
Place the pan in the center of the preheated oven. Bake until the cake is lightly golden brown all over, has begun to pull away from the sides of the pan, and a toothpick inserted in the center comes away with a few moist crumbs but no wet batter (about 35 minutes).
Remove the cake from the oven and place on a wire rack to cool in the pan for 10 minutes before transferring to a wire rack until ready to serve.
Slice and serve with fresh whipped cream and berries.