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

In a small bowl, combine chopped apples with 2 tablespoons granulated sugar and 1 teaspoon cinnamon; set aside.

In a large mixing bowl, cream together softened butter and 2/3 cup granulated sugar until light and fluffy.

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

Whisk together the flour and baking powder in a separate bowl.

Gradually add the dry ingredients to the butter mixture, alternating with 1/2 cup milk, stirring until just combined.

In another small bowl, mix the brown sugar and 1 teaspoon cinnamon for the swirl.

Pour half of the batter into the prepared loaf pan.

Spread half of the apple mixture over the batter, then sprinkle with half of the brown sugar cinnamon mixture.

Pour the remaining batter over the top, followed by the remaining apples and the rest of the brown sugar cinnamon mixture.

Use a knife to gently swirl the top layers into the batter.

Bake for 50 to 60 minutes, or until a toothpick inserted into the center comes out clean.

In a small bowl, whisk powdered sugar and 1 tablespoon milk until smooth.

Drizzle the glaze over the bread while it is still slightly warm.