Preheat oven to 350°F (175°C) and grease a 9x5 inch loaf pan.
In a large bowl, cream 1/2 cup softened butter and 1 cup sugar until light and fluffy.
Add eggs one at a time, beating well after each addition, then stir in the vanilla extract.
Whisk together flour, baking powder, and salt in a separate medium bowl.
Slowly add dry ingredients to the butter mixture, alternating with milk, mixing until just combined.
Transfer the batter to the prepared loaf pan and smooth the top.
Bake for 45 to 50 minutes, or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes before transferring to a wire rack.
Mix the remaining 1/4 cup sugar and 1 tablespoon cinnamon in a small dish.
Brush the warm loaf on all sides with melted butter and generously coat with the cinnamon-sugar mixture.