Line a large baking tray with parchment. In a heavy-bottomed saucepan place the brown sugar, honey
, butter, hoisin
sauce, and salt. Bring to a boil stirring to combine the butter and then boil without stirring until it reaches 140C/285F on a sugar thermometer
. Turn the heat off and add the bicarb and stir. Add in the popped corn and swirl to coat all pieces. Layout on the prepared baking tray immediately (as it cools it hardens).