Preheat oven to 350°F. Grease a 9-inch cake pan with nonstick spray and line the bottom of the pan with parchment paper cut into a circle. Dust the bottom and sides lightly with flour.
Combine and whisk flour, cornstarch, baking soda, baking powder, and salt in a medium bowl. Set aside.
Combine and whisk, using a hand mixer on medium, the stevia, olive oil, Zevia Ginger Beer Mixer, apple cider vinegar, dried ginger, vanilla, and fresh ginger. Continue to do so until smooth.
Add the dry mixture to the wet mixture, and mix until smooth with a hand mixer on low.
Fold in the fresh cranberries until well combined.
Add batter to the prepared pan and bake for 40-45 minutes, or until toothpick test comes out clean.