Preheat your oven to 350 degrees & spray a loaf pan with nonstick cooking spray. I like to use Baker’s Joy because it has the added flour - great for baked goods. In a small mixing bowl, whisk together the brown sugar and 1 teaspoon cinnamon. Set aside.
In a large bowl, cream the 2/3 cup granulated sugar and butter until light and fluffy with an electric mixer. Beat in the eggs one at a time and then add the vanilla. Mix until just combined. In a small bowl, whisk together the flour and baking powder. Add the flour mixture to the wet mixture; stir until combined. Add the milk and mix until smooth. Pour half of the batter into the prepared loaf pan and spread out evenly.
In a small mixing bowl, combine the apple filling ingredients. Pour half of the apples over the batter in the loaf pan, then spread on the remaining batter. Top with the rest of the apples and press the apples down slightly. Sprinkle the brown sugar and cinnamon mixture over top of the bread.
Bake at 350F for 70-75 minutes. Mix the optional glaze ingredients until smooth. Drizzle over the cooled bread, if desired.