Preheat your oven to 120C (250F). Line a large baking sheet with parchment paper and lightly spray it with non-stick cooking spray.
Melt the cannabutter over medium heat in a saucepan. Add the brown sugar, corn syrup, vanilla extract, baking soda, and salt to the melted cannabutter and stir until well combined.
Bring the mixture to a boil, stirring constantly, for about 5 minutes or until it reaches a temperature of 118°C (245°F) on a cooking thermometer.
While the mixture is cooking, cook your popcorn then place it in a bowl
Pour the hot cannabis infused toffee mixture over the popcorn, stirring until the popcorn is evenly coated.
Spread the toffee popcorn out in an even layer on the prepared and greased baking sheet.
Bake the infused toffee popcorn in the preheated oven for 30 minutes, stirring every 10 minutes.
Remove popcorn from the oven and let it cool completely on the baking sheet.
Once it has cooled down and hardened, break the cannabis infused toffee popcorn into pieces. Ready to eat, enjoy!