Mix the flour and sugar in a large bowl and set aside.
Add the oil, butter and water into a saucepan. Turn on medium high and bring to a boil.
Once the mixture starts boiling, pour it over the flour mixture. Use a hand mixer to beat until well blended.
Add the eggs, cinnamon, baking soda and buttermilk. Mix until well blended, scraping the sides of the bowl as needed.
Pour into the prepared pan and bake for 20-30 minutes or until the cake pulls away from the sides of the pan and the center tests done.
Add the butter, milk and 4 cups of powdered sugar into a small bowl. Use a hand mixer to beat until the frosting is creamy and completely mixed. Add more powdered sugar as needed to get to the consistency you’d like.