Preheat oven to 350°F (175°C). Line a 9×5-inch loaf pan with parchment paper and grease lightly.

In a medium bowl, whisk flour, baking powder, baking soda, salt, cinnamon, and nutmeg.

In a separate bowl, cream butter and granulated sugar until light and fluffy. Add eggs and vanilla extract, mixing well.

Add half the dry ingredients, followed by milk, then the remaining dry ingredients. Mix gently until combined.

Fold diced apples into the batter until evenly distributed.

Mix brown sugar and cinnamon to create the swirl mixture.

Pour half the batter into the loaf pan, sprinkle with half the cinnamon mixture, then repeat with the remaining batter and cinnamon mixture.

Use a knife to gently swirl the layers together.

Bake for 50–60 minutes or until a toothpick inserted in the center comes out clean.

Whisk powdered sugar, milk or cream, and vanilla to create the glaze.

Drizzle glaze over the warm bread, slice, and serve.