Preheat the oven to 350°F. Spray a 9x13 baking dish with nonstick cooking spray.

Add the flour, baking powder, baking soda and salt to a small bowl and whisk to combine.

In a large bowl, using a handheld mixer on medium high speed, beat the softened butter until smooth. (About 1 ½ - 2 minutes)

Add the granulated sugar and continue to mix on medium high speed for another 1 ½ - 2 minutes until well combined and fluffy.

Lower the mixer speed to medium low and add the vanilla extract and the eggs and egg yolks, beating well until completely incorporated.

Next alternate adding the flour mixture and buttermilk, mixing just until incorporated after each addition ending with the buttermilk.

Add the brown sugar and ground cinnamon to a small bowl, stirring to completely combine.

Spread half of the cake batter to the prepared baking dish. Using an offset spatula or a large spoon, smooth the cake batter over the bottom of the pan.

Sprinkle the brown sugar and cinnamon mixture evenly over the bottom layer of cake batter. (You can use a knife to swirl the cinnamon layer)

Spread the remaining cake batter evenly over the brown sugar and cinnamon layer. Bake uncovered for 35 minutes or until a toothpick inserted comes out with only a few moist crumbs.

About 5 minutes before the cake is finished baking, in a small bowl, whisk together the powdered sugar, milk, honey and vanilla extract until completely smooth.

Immediately after removing the cake from the oven, drizzle the glaze over the cake. Use an offset spatula to spread the glaze. Allow the cake to cool for about 25 - 30 minutes before cutting into 12 equal slices and serving. (If you prefer, you can allow the cake to cool completely before serving)