Preheat your oven to 350°F (175°C). Grease a 9-inch round cake pan and line the bottom with parchment paper.
In a medium bowl, combine the diced apples with 1 tablespoon of granulated sugar and a sprinkle of cinnamon. Toss until coated and set aside.
In a large mixing bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt.
In another bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Beat in the eggs, one at a time, followed by the vanilla extract. Mix until fully incorporated.
Gradually mix in the dry ingredients, alternating with the buttermilk, starting and ending with the dry mix. Stir until just combined.
Fold in the prepared apples gently, ensuring they are evenly distributed throughout the batter.
Pour the batter into the prepared cake pan and smooth the top with a spatula.
Bake in the preheated oven for 35-40 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then carefully transfer it to a wire rack to cool completely.
For the glaze, whisk together the powdered sugar and milk until smooth and drizzling consistency. Adjust thickness if needed by adding more powdered sugar or milk.
Once the cake is completely cool, drizzle the glaze over the top of the cake. Optionally, sprinkle with more cinnamon for added flavor.
Notes
Optional to sprinkle extra cinnamon for added flavor.