Preheat oven to 350°F (175°C).
In a large mixing bowl, combine the flour, sugar, baking powder, and cinnamon. Mix until combined.
Add the eggs, melted butter, and milk. Mix until the batter is smooth.
Add the diced apples and stir until evenly distributed.
Pour the batter into a greased 9x5-inch (23x13 cm) loaf pan.
Sprinkle a mixture of cinnamon and sugar on top.
Bake for 25 minutes, or until a toothpick inserted in the center comes out clean.