Preheat your oven to 350°F (175°C) and grease a 9x5-inch loaf pan with butter or cooking spray, then dust with flour.

In a medium bowl, combine the light brown sugar and cinnamon, stirring well.

In a large mixing bowl, beat together the white sugar and softened salted butter until creamy and pale.

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

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

Pour half of the batter into the prepared loaf pan, followed by half of the apples and half of the cinnamon-sugar mixture.

Spread the remaining batter on top, then add the rest of the apples and cinnamon-sugar mixture.

Use a knife or skewer to gently swirl the batter for a marbled effect.

Bake for 50-60 minutes until golden brown and a toothpick comes out clean.

Cool the bread in the pan for about 10 minutes, then transfer to a wire rack. Prepare the glaze by mixing powdered sugar and milk until smooth.