Preheat oven to 350°F. Spray a 9-inch round cake pan with nonstick spray and line the bottom with parchment paper.
Add the granulated sugar and lemon zest to a large mixing bowl. Rub the zest into the sugar to help release some of the natural oil/flavor.
Whisk in the gluten-free flour, cornstarch, xanthan gum, baking powder, baking soda, and salt. Set aside.
In a medium bowl, whisk together the olive oil, yogurt, eggs, and lemon juice. Add the wet ingredients to the dry ingredients and mix until fully incorporated.
Transfer the batter to the prepared baking pan and bake 25-30 minutes or until a cake tester comes out clean.
Cool completely before serving. Serve with a dusting of powdered sugar, homemade whipped cream, and/or fresh berries.
Notes
Store the cake at room temperature, tightly wrapped, or in an airtight container.