Step 1: Preheat oven to 350 degrees. Grease and flour a loaf pan.
Step 2: Add flour, sugar, baking powder, baking soda, cinnamon, salt, buttermilk. oil, eggs, and vanilla
Step 3: In a large mixing bowl. With an electric mixer, beat the ingredients for 3 minutes.
Step 4: Pour the batter into the prepared loaf pan. Use an offset spatula to smooth the top of the batter. Set aside.
Step 5: Add sugar, cinnamon, and melted butter in a small bowl. Sprinkle topping on the top of the loaf of bread.
Step 6: Use a knife cut in a light swirling motion for a marbled effect.
Step 7: Bake at 350 degrees for 50 minutes. Test the center of the loaf of bread by inserting a toothpick. If it comes out clean, remove it from the oven to cool.
Step 8: Set it aside for a few minutes to cool before slicing.