Preheat oven to 400.
Combine cranberries and Guinness® Extra Stout. Microwave on high for 45 seconds and let it steep and cool, to allow those cranberries to saturate with all that lovely beer flavor. Strain and set aside.
Mix together flour, baking powder, baking soda, salt and sugar. In a separate bowl, whisk together egg, buttermilk and melted butter. Combine the dry and wet ingredients until just mixed. Do not over mix, you just want all the dry ingredients hydrated.
Gently fold in cranberries and walnuts.
Spray muffin tin with a liberal amount of non-stick cooking spray. Fill each section about ¾ of the way up. Top with a pinch flakey sea salt and demerara. Bake for about 18-25 minutes or until a toothpick or cake tester comes out clean.
Cool for 5 minutes and quickly remove each muffin from the tin and finish cooling on a wire rack.
Whipped Maple Cinnamon Butter
Using a whisk, whip butter until everything is combined. Season to taste. Use on everything!