3. Add the sugar, egg, baking soda, vanilla, salt, and flour to the bowl. Stir gently to incorporate and make sure everything is well combined.
5. Grease your cast iron skillet with butter or cooking spray, then pour the batter into the pan. Note: try to push the batter away from the middle, so when it rises it will be even!
6. Bake for 40 minutes until nice and golden brown on top. To test, insert a toothpick and if it comes out clean, it’s done. Let cool, slice and serve!