01 -
Preheat the oven to 350°F (175°C). Grease a 9×5-inch loaf pan or line with parchment paper.
02 -
In a large bowl, whisk together the flour, granulated sugar, baking powder, baking soda, and salt.
03 -
In a separate bowl, whisk together buttermilk, melted butter, eggs, and vanilla extract until smooth.
04 -
Gradually mix the wet ingredients into the dry ingredients, stirring gently until just combined. Do not overmix.
05 -
In a small bowl, mix together the brown sugar and cinnamon for the swirl.
06 -
Pour half of the batter into the prepared loaf pan. Sprinkle half of the cinnamon-sugar mixture over the batter. Repeat with the remaining batter and cinnamon-sugar. Gently swirl through the batter with a knife to create a marbled effect.
07 -
Bake for 50–60 minutes, or until a toothpick inserted in the center comes out clean.
08 -
Cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
09 -
Brush the top of the warm bread with melted butter. Mix granulated sugar and cinnamon for the topping and sprinkle over the top.
10 -
Slice and serve.