1️⃣ Preheat oven to 350°F (175°C). Grease a 9×5-inch loaf pan.

2️⃣ Prepare the apple mixture: In a small bowl, toss diced apples with 1 tablespoon sugar and 1 teaspoon cinnamon. Set aside.

3️⃣ Make the batter: In a large bowl, cream together butter and granulated sugar until light and fluffy. Beat in eggs one at a time, then stir in vanilla extract.

4️⃣ Combine dry ingredients: In a separate bowl, whisk together flour, baking powder, and salt. Gradually add to the wet mixture, alternating with milk, and mix until just combined.

5️⃣ Layer the bread: Pour half of the batter into the loaf pan. Sprinkle with half of the cinnamon-sugar apples and half of the brown sugar-cinnamon mixture. Repeat with the remaining batter and apple mixture.

6️⃣ Swirl the layers: Use a knife to gently swirl the layers together for a marbled effect.

7️⃣ Bake for 50-60 minutes, or until a toothpick inserted in the center comes out clean. If the top browns too quickly, cover loosely with foil for the last 15 minutes.

8️⃣ Cool in the pan for 15 minutes, then transfer to a wire rack to cool completely.

9️⃣ Make the glaze: Whisk together powdered sugar, milk, and vanilla extract. Drizzle over the cooled bread.