Preheat oven to 350, and grease the 9-inch cake pan.
In a large bowl add eggs, oil, milk, vanilla extract and beat until well combined.
In another bowl add flour, sugar, baking soda, salt and mix very well. Add the dry mixture to the wet mixture and mix until well combined. Set bowl aside.
In another bowl add brown sugar, cinnamon, and mix until well combined.
Add half the batter into the cake pan and spread evenly on the pan.
Add half of the sugar cinnamon mix and spread evenly on the batter using a fork.
Next, carefully add the remaining batter on top of the sugar-cinnamon mix.
Lastly, top with the remaining cinnamon sugar mixture.
Bake for 40-45 minutes or when toothpick is inserted and comes out dry.