1 box (about 18.25 ounces) lemon cake mix (look for a sugar-free or low-sugar option )
1 can (12 ounces) diet lemon-lime soda (such as Sprite Zero or Diet Sierra Mist)
1 cup fat-free Greek yogurt (plain or lemon-flavored)
Instructions:
Preheat your oven to the temperature specified on the cake mix box.
In a mixing bowl, combine the lemon cake mix and the can of diet lemon-lime soda. Stir until well combined and there are no lumps.
Pour the cake batter into a prepared cake pan. You can use a bundt pan, round cake pan, or any other type of pan you prefer.
Bake the cake according to the instructions on the cake mix box, or until a toothpick inserted into the center comes out clean.
Once the cake is done baking, remove it from the oven and let it cool completely.
While the cake is cooling, prepare the frosting by mixing the fat-free Greek yogurt with a little lemon zest if desired. Spread the yogurt frosting over the cooled cake.