Preheat your oven to 350°F (175°C) and grease a loaf pan.
In a mixing bowl, cream together the softened butter, C&H Granulated Sugar, and C&H Light Brown Sugar until the mixture is pale and fluffy.
Add the eggs, vegetable oil, and vanilla extract to the bowl, mixing until smooth.
Pour in the buttermilk or Eggnog and stir to combine all the wet ingredients.
In a separate bowl, whisk together the dry ingredients: all-purpose flour, baking powder, salt, and cinnamon.
Gently combine the wet and dry mixtures until just mixed.
To prepare the cinnamon filling, mix the melted butter, C&H Light Brown Sugar, C&H Granulated Sugar, and cinnamon in a small bowl and set aside.
To layer the loaf, pour half of the batter into the prepared pan, then spoon some of the cinnamon mixture over the batter. Add the remaining batter on top and swirl it a few times to combine.
Bake in the preheated oven for 50 to 60 minutes, or until a toothpick inserted into the center comes out with moist crumbs.
Allow the loaf to cool for ten minutes in the pan.
Brush the top with 1 tablespoon of melted butter and sprinkle with additional cinnamon sugar.
Once fully cooled, slice the loaf for clean cuts.
