Preheat your oven to 350°F (175°C). Grease the loaf pan.
In a mixing bowl, cream together the softened butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla extract.
Mix in the buttermilk, flour, and baking soda until well combined.
In a separate bowl, mix the cinnamon and sugar for the topping.
Pour half of the batter into the prepared loaf pan. Sprinkle half of the cinnamon-sugar mixture over it. Pour the remaining batter and top with the rest of the cinnamon-sugar mixture.
Bake for 60 minutes or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes before transferring it to a wire rack.
Notes
This bread is best served warm and can be stored in an airtight container for several days.