Microwave pop two bags of Orville Redenbacher’s Naturals Simply Salted popcorn. Pour into a large metal bowl. Remove any unpopped kernels. Butter the sides of a medium sized pot. Add everything except baking soda and vanilla. Bring ingredients to a boil over medium heat while stirring constantly. After the ingredients are boiling, let it continue to boil for 5 minutes without stirring.
After boiling for 5 minutes, remove the pot from the heat. Stir in vanilla and baking soda. The baking soda will cause the mixture to foam up a bit. After it gets foamy, pour it over the popcorn and mix until the popcorn is covered with the mixture.
Spread popcorn into to large greased baking pans. Bake at 250° for 1 hour, stirring every 10 minutes. Remove from pans and place on parchment paper to cool. If you can keep from eating it all right away, store what’s left in an airtight container or tightly closed plastic bag.