Preheat oven to 350°F (175°C). Grease and flour an 8 x 5 inch loaf pan or line it with parchment paper.

In a small bowl, whisk together brown sugar and cinnamon. Set aside.

In a large mixing bowl, whisk together eggs and granulated sugar until well combined.

Stir in melted butter and vanilla extract until smooth.

Add flour, baking powder, baking soda, and salt. Mix until just combined; the batter will be thick.

Gently fold in the chopped apples.

Pour half of the batter into the prepared loaf pan and sprinkle three-quarters of the brown sugar mixture over it.

Carefully spread the remaining batter on top of the brown sugar mixture and sprinkle the remaining cinnamon sugar over the top, swirling gently into the batter.

Bake for 35 to 45 minutes, until the top is golden and a toothpick inserted comes out clean or with just a few moist crumbs. Tent with foil if browning too quickly.

Let the bread cool completely before slicing and serving.