Preheat oven to 325°F. Grease and flour one 8-inch round cake pan.
In a small bowl, stir together flours and baking powder.
In a small saucepan, combine chocolate chips, butter and oil and heat on low until chocolate is melted.
In an electric mixer bowl, whisk together eggs, Splenda Stevia Sweetener, buttermilk, vanilla, and salt. Slowly add chocolate mixture with an electric mixer on low speed until mixture is well blended.
Slowly add flour mixture and mix until smooth.
Pour batter into prepared pans. Bake for 20 minutes until a wooden pick inserted into center of cake comes out clean.
Cool cake in cake pan, then run a thin metal spatula around rim to loosen cakes. Transfer to a wire rack to cool completely before frosting as desired.
