Preheat the oven to 350°F.
In a large bowl, combine the flour with the baking powder, baking soda, salt, and cinnamon and stir until well incorporate.
In another bowl, stir vegetable oil with the sugar, eggs and vanilla.
Pour dry mixture into the wet mixture and whisk them until well blended.
Pour slowly into a greased round pan.
Place into the preheated oven and bake it for 25 to 30 minutes or until inserted toothpick comes out clean.
Remove the cake out from the oven and let it cool completely.
Slice to serve. Enjoy it!