Preheat your oven to 350°F (175°C) and prepare a loaf pan with nonstick spray.

In a medium bowl, combine diced apples, 1 tablespoon of dark brown sugar, and 1.5 teaspoons of ground cinnamon. Drizzle melted butter over the apple mixture and mix gently.

In a small bowl, mix together ½ cup of brown sugar and 2 teaspoons of ground cinnamon for the layering.

In a stand mixer, cream the softened butter and granulated sugar together until light and fluffy (about 2-3 minutes).

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

In a separate bowl, whisk together milk and sour cream until smooth.

In a large bowl, combine flour, baking powder, and a pinch of salt. Gradually add this to the creamed mixture, alternating with the milk mixture.

Spread half of the batter into the prepared loaf pan, layer with half of the apple mixture followed by half of the cinnamon sugar. Repeat with remaining batter and toppings.

Bake for about 50 minutes until golden brown and a toothpick inserted comes out mostly clean.

While baking, whisk together powdered sugar, 1 tablespoon of milk, and ¼ teaspoon of vanilla until smooth for the glaze.

Once out of the oven, let the bread cool slightly before drizzling the glaze on top.