Begin by peeling, coring, and dicing your large Gala apple into small pieces. In a mixing bowl, combine the diced apples with ½ cup of light brown sugar, 1 tablespoon of all-purpose flour, and 2 teaspoons of apple pie spice blend. Toss until the apples are well-coated and set aside.
In another mixing bowl, whisk together 1 cup of all-purpose flour, 1 teaspoon of baking powder, ½ teaspoon of baking soda, and ½ teaspoon of salt. This will ensure even distribution of the leavening agents.
In a large mixing bowl, beat together ½ cup of unsalted butter and ½ cup of granulated sugar until light and fluffy. This should take about 2-3 minutes.
Add in 1 large egg and 2 teaspoons of vanilla extract to the butter mixture. Mix until well combined.
Pour in ½ cup of buttermilk and mix until just combined. The batter will be slightly lumpy, which is perfectly fine.
Gradually fold the dry mixture into the wet mixture using a rubber spatula. Be careful not to over-mix; you want a thick batter.
Gently fold in the apple mixture until evenly distributed throughout the batter.
Pour the batter into a greased 9x5-inch loaf pan and smooth out the top. Bake in a preheated oven at 350°F (175°C) for 50-60 minutes or until a toothpick inserted in the center comes out clean.
Once baked, allow the bread to cool in the pan for about 10 minutes before transferring it to a wire rack. While the bread cools, whisk together 1 cup of sifted powdered sugar and 2 tablespoons of heavy cream to create the glaze. Drizzle it over the warm bread once it has completely cooled.
