Preheat your oven to 175 degrees C and grease a loaf pan.
In a large mixing bowl, combine the flour, sugar, baking powder, bi carb soda, cinnamon and salt. In another bowl, whisk together the eggs, buttermilk, melted butter, and vanilla until well combined.
Add the wet ingredients into the dry ingredients, stirring until just combined.
Pour the batter into the prepared loaf pan and smooth the top.
In a small bowl, mix together the topping sugar and cinnamon, then sprinkle it evenly over the batter.
Bake for 50 – 60 minutes or until a toothpick inserted in the centre comes out clean.
Let it cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.