1
To a pot, add coconut oil over medium heat. Add popcorn and cover with lid. Shake pot while popcorn pops. Remove from heat when there are 2-3 seconds between pops. Salt popcorn to taste. Pour popcorn in an even layer on a parchment paper lined baking sheet.
2
To a sauce pan, melt butter. Keep heat medium low so that butter down to brown. Once melted, add brown sugar. Stir to completely combine. Once combined, let mixture come to a low boil for 5 minutes and stop stirring. Stir in vanilla for about a minute. Add in baking soda. Caramel will react by bubbling up. Remove from heat. Pour over popcorn and fold to cover every kernel. Let cool.
3
Preheat oven to 225°F. Pop popcorn in oil over medium heat. Remove any unpopped kernels and place popcorn in a large roasting pan or baking sheet.
4
In a large heavy pot combine butter, brown sugar, corn syrup, and salt. Cook over medium heat, stirring until melted and smooth. Bring to a boil. Once boiling, stop stirring. If using a candy thermometer, cook until caramel reaches 242 to 243 degrees Fahrenheit. If you do not have a thermometer, let the caramel boil for about 4 minutes over medium heat once it reaches a steady rolling boil. Remove from heat immediately. Stir in vanilla and baking soda. The caramel will foam up.
5
Pour caramel over warm popcorn and toss continuously until evenly coated. Bake at 225°F for 45 minutes, stirring every 15 minutes. Spread onto parchment paper and sprinkle with flaky sea salt while still warm. Let cool completely before breaking apart and storing in an airtight container.