Method
Pour the popped popcorn in a large, wide bowl.
Preheat an oven to 250°F / 120°C. Line two heavy, rimmed baking sheets with Silpats or parchment paper. Spread the peanuts across one of the pans and roast in the hot oven, stirring regularly, until aromatic and golden, about 10 minutes. Season with salt, scatter the nuts onto the popcorn, Set both prepared baking pans aside.
Scrape the butter into a medium, heavy-bottomed saucepan. Tip in the sugar, corn syrup and water. Set over medium heat and cook, stirring regularly, until the sugar is dissolved. Increase the heat to medium-high and bring to a boil without stirring. (If any sugar clings to the side of the pan, dissolve with a wet heat-safe pastry brush.) Continue to cook, swirling the pan regularly, until the sugar turns evenly golden and reaches 250°F / 120°C, around 5 minutes. Stir in hot sauce with a heatproof spatula and cook for 1 minute more, continuing to stir all the while. Pull the saucepan from the heat and quickly stir in baking soda (it will bubble up enthusiastically).
Carefully pour the caramel over the popcorn and fold to coat the kernels. Divide the popcorn between the two prepared pans and spread into even layers.
Bake the popcorn in the hot oven for 30 minutes, turning occasionally with a wide, greased spatula. After the 30 minutes are up, sprinkle unevenly with pink salt and chile powder, so there are rusty patches. Bake for 5 minutes more. The kernels should be thinly coated and shining when ready.
Leave the popcorn to cool completely on the trays. Break up any large clumps then transfer to an airtight container for up to 1 week.
