Preheat your oven to 350°F (175°C) and grease a 9x5 inch loaf pan.

In a large bowl, whisk together the flour, sugar, baking powder, and salt until well combined.

In a separate bowl, mix the melted butter, milk, and eggs until smooth.

Gradually fold the wet ingredients into the dry mixture, stirring until just combined.

In a small bowl, combine the cinnamon and brown sugar.

Pour half of the batter into the prepared loaf pan, then sprinkle half of the cinnamon mixture on top.

Add the remaining batter and finish with the remaining cinnamon mixture. Use a knife to swirl the cinnamon into the batter gently.

Bake for 50-60 minutes or until a toothpick inserted in the center comes out clean.

Allow the bread to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.