Preheat oven to 350ᵒF. Spray a glass bread pan with nonstick cooking spray. In a medium bowl, whisk together flour, baking soda, baking powder, and salt.
In a medium bowl, beat together butter and Splenda Stevia Sweetener. Mixture will come apart into little balls, and then come back together as you continue beat. Add eggs, one at a time, beat well after each addition. Beat in vanilla.
Add flour mixture in two parts, alternating with the buttermilk, and mixing on low until everything is incorporated. Scrape down sides of the bowl with a spatula. Fold in orange zest and cranberries.
Spread mixture into prepared pan. Bake, uncovered, for 30 minutes, or until a toothpick comes out clean. Remove and let cool 15 minutes before removing from pan. Gently run a knife around the edges to help bread remove from pan. Transfer loaf to a wire rack to let completely cool before icing.
For the icing, add white chocolate chips and coconut oil to a small, microwavable safe bowl. Microwave on half power starting a minute. Remove and stir. Keep microwaving at 20 second intervals until chips are melted (white chocolate can burn easily). Once melted and smooth, spread a thin layer of icing on top of loaf, letting it drip down the sides slightly.
If desired, top with a few chopped dried cranberries or more orange zest. Enjoy!