In a small bowl, combine 1/3 cup brown sugar and 1 teaspoon ground cinnamon. Set aside.
Prepare the Batter:
Preheat your oven to 350°F (175°C). Grease and flour a 9×5-inch loaf pan.
In a large bowl, cream together the 2/3 cup granulated sugar and softened butter until light and fluffy.
Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
In a separate bowl, whisk together the flour and baking powder.
Add the flour mixture to the butter mixture alternately with the milk, starting and ending with the flour mixture. Mix until just combined.
Assemble the Bread:
Pour half of the batter into the prepared loaf pan, spreading it evenly.
Add half of the chopped apples on top of the batter. Sprinkle the apples with half of the cinnamon sugar mixture.
Pour the remaining batter over the apples and spread evenly.
Top with the remaining apples and sprinkle with the remaining cinnamon sugar mixture.
Bake:
Bake in the preheated oven for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for about 15 minutes before transferring it to a wire rack to cool completely.
Make the Glaze:
In a small bowl, whisk together the powdered sugar and milk until smooth. If the glaze is too thick, add more milk, a little at a time, until it reaches your desired consistency.
