Created by Sknymini on February 22, 2015
Step 1: Heat oven to 350°E Lightly coat an 8-inch springform pan with cooking spray.
Step 2: Whisk together flour, baking soda, baking powder, and salt in a large bowl; form a well in the center.
Step 3: Beat egg whites with an electric mixer at high speed in a medium bowl until stiff peaks form, about 3 minutes.
Step 4: Beat egg yolks, sugar substitute, buttermilk, oil, lemon extract, and lemon zest in a medium bowl at medium speed until smooth, about 1 minute.
Step 5: Pour egg yolk mixture into the center of the dry ingredients; stir gently until just combined. Gently fold in half of the egg whites, then fold in the remaining egg whites.
Step 6: Pour batter into pan and bake until edges are lightly browned and a toothpick inserted in the center of the cake comes out clean, 25 to 28 minutes. Let cool in the pan for 5 minutes; remove from the pan and transfer to a wire rack. Cut into wedges and serve warm or at room temperature.