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

In a medium bowl, combine diced apples with brown sugar and ground cinnamon.

In a large mixing bowl, cream together unsalted butter and granulated sugar until light and fluffy.

Add the eggs one at a time, beating well after each addition, then stir in the vanilla extract.

In a separate bowl, whisk together all-purpose flour and baking powder, then gradually add to the butter mixture, alternating with milk.

Pour half of the batter into the loaf pan, layer half of the apple mixture, then repeat with remaining batter and apple mixture.

Bake for 50-55 minutes, until a toothpick comes out clean.

Remove from oven and cool for about 10 minutes before transferring to a wire rack.

In a small bowl, whisk together powdered sugar, milk, and vanilla extract until smooth to make the glaze.

Drizzle the glaze over the cooled bread before serving.