01 -  Preheat oven to 350°F (175°C). Grease and line a 9x5-inch loaf pan with parchment paper. 
 02 -  In a small bowl, toss diced apples with granulated sugar and ground cinnamon. Set aside. 
 03 -  Mix packed brown sugar and ground cinnamon in a separate bowl. Set aside. 
 04 -  In a large mixing bowl, beat softened butter with granulated sugar until light and fluffy. Add eggs one at a time, mixing thoroughly, then incorporate vanilla extract. 
 05 -  Combine all-purpose flour, baking powder, and salt in a bowl. Alternately add dry mixture and milk to the creamed butter mixture, starting and ending with flour. Mix until just combined. 
 06 -  Spread half of the batter evenly in the prepared pan. Distribute half of the apple mixture atop, followed by half the cinnamon swirl mixture. Repeat layering with remaining batter, apples, and swirl. 
 07 -  Use a butter knife to gently swirl the batters and fillings together. 
 08 -  Bake in the preheated oven for 50–60 minutes or until a toothpick inserted in the center comes out clean. 
 09 -  Allow the loaf to cool in the pan for 15 minutes before transferring to a wire rack to cool completely. 
 10 -  In a small saucepan over medium heat, melt granulated sugar, swirling occasionally, until it becomes amber in color. Add unsalted butter and stir until melted. Gradually whisk in heavy cream; mixture will bubble. Remove from heat, stir in flaky sea salt, and let cool slightly. 
 11 -  Drizzle cooled loaf with salted caramel glaze before serving.