1 teaspoon flake salt or smoked flake salt, for finishing
How to Make It
Place the oil and popcorn in a large pot and cover with a lid. Place over medium-high heat. Shake the pot occasionally over the burner until the popping mostly subsides, about 2 seconds between pops. Pour the popcorn into a very large bowl.
Preheat the oven to 250°F. Line a baking sheet with parchment paper.
In a medium saucepan over medium-high heat, melt the butter with the brown sugar, salt, corn syrup, and maple syrup and bring to a boil. Gently boil for 5 minutes, stirring occasionally. Add the peanuts to the toffee and then drizzle over the popcorn. Stir carefully to evenly coat the popcorn. Spread onto the prepared baking sheet and bake for 1 hour, stirring and rotating the pan halfway through. Sprinkle with flake salt to finish and then let cool to room temperature. The toffee popcorn can be made up to 3 days ahead. Store in an airtight container once thoroughly cooled.