-
For the cake: Place an oven rack in the center of the oven. Preheat the oven to 350 degrees F.
-
In a large mixing bowl, combine the egg whites, salt and cream of tartar. Using an electric hand mixer, beat on medium speed until frothy.
-
Add the vanilla extract, lemon juice, and lemon zest. Beat on high speed until soft peaks form, about 2 to 4 minutes.
-
Gradually add the sugar and beat until the mixture forms stiff peaks, about 2 minutes longer.
-
Sprinkle the flour over the egg white mixture.
-
Using a spatula, carefully fold in the flour until incorporated.
-
Spoon the batter into an ungreased 10-inch nonstick angel food cake pan.
-
Bake for 30 to 40 minutes until the top is browned and a skewer inserted halfway between the inner and outer wall of the pan comes out clean.
-
Invert the pan on a wire rack to cool completely, about 1 hour.
-
For the sauce: In a small bowl whisk together the yogurt, honey, and lemon juice until smooth.
-
Using a spatula, loosen the cake around the sides and middle. Release the cake and place on a serving plate.
-
Cut into slices and drizzle with the sauce.