Preheat the oven to 350°F and grease a 9x5-inch loaf pan, or line it with parchment paper.

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

In a large bowl, whisk together the granulated sugar, brown sugar, eggs, vegetable oil, milk, and vanilla extract until smooth and glossy.

Add the dry ingredients to the wet ingredients and stir just until combined.

Gently fold in the chopped apples until evenly distributed.

In a small bowl, mix the brown sugar and cinnamon for the swirl.

Pour half of the batter into the prepared loaf pan.

Sprinkle half of the cinnamon sugar mixture over the batter.

Add the remaining batter, then sprinkle the remaining cinnamon sugar on top.

Use a butter knife to gently swirl the cinnamon sugar through the batter with a few figure-eight motions.

Bake for 50–60 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs.

If the top browns too quickly, loosely cover it with foil during the last 10–15 minutes.

Let the bread cool in the pan for 15 minutes.

Lift the loaf out and cool on a wire rack before slicing.