Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan and set aside.
In a large mixing bowl, whisk together the flour, 1 cup of sugar, baking powder, salt, and 1 teaspoon of cinnamon until well combined.
In another bowl, combine the melted butter, milk, eggs, and vanilla extract. Mix until smooth.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix; a few lumps are okay.
Pour half of the batter into the prepared loaf pan.
In a small bowl, mix together the 1/4 cup sugar and 1 tablespoon cinnamon. Sprinkle half of this mixture over the batter in the loaf pan.
Pour the remaining batter on top and sprinkle the rest of the cinnamon sugar mixture over the top.
Bake in the preheated oven for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Allow the bread to cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely.