Combine brown sugar and cinnamon in a small bowl and stir to combine. Set aside.

Remove the peel from the apple and chop into small pieces. Place in a bowl and set aside.

Combine softened butter and granulated sugar in a large bowl and mix on low/medium using a hand or stand mixer.

Add the eggs and vanilla extract to the large bowl. Continue to mix on low/medium until smooth.

Add the flour, baking powder, and sea salt to the bowl and stir to combine. Lastly, add the milk and stir with a spoon until incorporated.

In a greased 9x5 inch loaf pan, add half the batter then top with half of the chopped apples, followed by half of the brown sugar mixture. Repeat this layering one more time.

Place the apple bread in the oven on the center rack at 350 degrees F for 50-55 minutes or until an inserted toothpick comes out clean.

Once finished, let stand in the pan for 10 minutes then remove, slice, and enjoy warm.