Begin preheating the oven to 350° F (176° C) and lightly grease a 9x5 loaf pan with baking spray or lightly grease and lightly flour or use lightly greased parchment paper.
Cinnamon sprinkle:
In a small bowl, mix the brown sugar with the 1 teaspoon of cinnamon, breaking up any clumps. Set aside.
Apples:
In a larger bowl, combine the cut apples with 1 teaspoon of cinnamon and the 2 tablespoons of granulated sugar. Set aside.
Fritter bread batter:
In the bowl of a mixer, add the 2/3 cup of sugar with the butter and cream together for about 2-3 minutes until light and fluffy.
Add the eggs one at a time and mix well, then add the vanilla. Make sure to scrape the bowl well several times.
With the mixer on low speed, add the flour, baking powder, and salt and combine until barely mixed together. Pour in the milk and stir until just blended enough. Turn off the mixer and scrape the bowl well with a spatula, stirring to mix by hand a couple times. Do not over mix.
Scoop half of the batter into the greased baking pan and spread it evenly. Add half of the apple mixture atop the batter and sprinkle half of the cinnamon/brown sugar mix atop the apples. Pour the remaining batter into the pan and repeat with the apples and cinnamon/brown sugar. Lightly press the apples and brown sugar mix into the top.
Place the pan in the oven and bake for 50-60 minutes, until nicely browned and a toothpick poked in the center comes out clean, with a few moist crumbs. Bypass piercing any apples to avoid confusion.
Remove the pan from the oven and cool on a rack for about 10-15 minutes. Run a knife or spatula around the edges if necessary, flip the loaf out and onto the cooling rack to cool thoroughly.
To make the glaze, stir the powdered sugar and milk together until dissolved and drizzle over the loaf once it has cooled.