Preheat oven to 350°F (175°C). Grease and flour a 9x5-inch loaf pan or line it with parchment paper.

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

In a separate large bowl, whisk both sugars, oil, eggs, milk, and vanilla until well combined.

Gradually add the dry ingredients to the wet ingredients and stir just until combined.

Fold in the chopped apples.

In a small bowl, mix together the cinnamon sugar swirl ingredients.

Pour half of the batter into the prepared pan. Sprinkle half of the cinnamon sugar mixture over the batter.

Add remaining batter, then top with the rest of the cinnamon sugar. Use a knife to gently swirl the cinnamon sugar into the batter.

In another small bowl, prepare the crumb topping by mixing flour, brown sugar, cinnamon, and melted butter. Sprinkle evenly over the batter.

Bake for 55–60 minutes or until a toothpick inserted in the center comes out clean.

Allow the bread to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.