Preheat oven to 325°F and grease a 9x13" baking dish.
Add the flour, baking powder, baking soda and salt to a mixing bowl and mix well with a whisk. Set aside.
2-½ Cups All Purpose Flour, 2 teaspoons Baking Powder, ½ teaspoon Baking Soda, ½ teaspoon Salt
Add the butter and granulated sugar to the bowl of a stand mixer and beat with the wire whip until creamy, about 3-4 minutes.
10 Tablespoons Unsalted Butter, 1-½ Cups Granulated Sugar
Add the eggs and egg yolks one at a time while still beating.
2 Each Large Eggs, 2 Each Egg Yolks
Add the vanilla and sour cream and beat again until totally mixed, scraping the sides as needed.
2 teaspoons Vanilla Extract, ½ Cup Sour Cream
Add about ½ cup of the flour mixture and keep mixing, followed by some of the buttermilk. Alternate until everything is incorporated, ending with the flour mixture.
1 Cup Buttermilk
In a small bowl, mix together the sugars and cinnamon until totally combined.
1 Cup Light Brown Sugar, 3 Tablespoons Granulated Sugar, 1 Tablespoon Ground Cinnamon
Pour half of the cake batter into the prepared baking dish. Shake the dish so that it levels out.
Sprinkle half of the cinnamon sugar on top of the batter, evenly.
Top with the remaining cake batter and spread carefully and evenly to all sides and corners.
Sprinkle the remaining cinnamon sugar on top, evenly.
Using a toothpick, swirl the sugar into the cake batter (just the top layer).
Add to the oven and bake for 45 minutes, add a foil tent toward the end if you see it is browning too much.
Remove from the oven and allow to cool for 10 minutes, while you prepare the vanilla glaze.
In another mixing bowl, add the powdered sugar, melted butter, honey, vanilla and milk. Pour over the top of the warm cake, evenly. Spread with the back of a spoon to cover all the cake.
2 Cups Powdered Sugar, 2 Tablespoons Unsalted Butter, 1 Tablespoon Honey, 1 teaspoon Vanilla Extract, ¼ Cup Milk
Allow to cool completely, firm up the glaze in the refrigerator for 30 minutes if needed.