Pre-heat oven to 375 degrees. Spray muffin tin with non-stick cooking spray and set aside.
Zest the oranges and finely chop the zest, set aside. Juice the oranges and set aside the juice.
Use a food processor to coarsely chop the cranberries and walnuts. Feel free to use a knife to chop the cranberries and walnuts. Set mixture aside.
In a large bowl, whisk flour, baking powder, and the 1/2 cup of sugar. Set aside.
In a medium bowl, whisk together the orange juice, melted butter and egg to blend ingredients together.
Slowly whisk together the orange juice mixture into the flour mix. Stir to just combine ingredients. Add in the cranberries, nuts and orange zest to gently combine ingredients.
Divide the batter evenly into the 12 muffin tins. Sprinkle the Tablespoon of sugar evenly on the muffins.
Bake the muffins for 25 minutes. Use a toothpick to check if muffins are done. Insert a toothpick into the center of the muffins. Toothpick should come out clean. Remove muffin tray from oven and let cool. Store muffins wrapped in plastic wrap or in a covered tin,
Any nutritional data I provide is an approximation and actual dietary information can vary based on ingredients and portion sizes.