Heat oven to 250; line two rimmed baking sheets with parchment paper.
Pour oil and corn into a large pot; cover, heat over medium high and when sound of popping slows down, turn off the heat, slide the lid open just enough to let steam, but not wayward popcorn explosions, escape; pick out any old maids (unpopped kernels) and set aside.
Mix molasses, sugar and corn syrup in a large saucepan; bring to a boil over high heat until the mixture reaches the hard-ball stage on a candy thermometer, 260; stir in the butter, then the baking soda and salt.
The mixture will turn a light caramel color and rise up in a bubbling mass; be prepared but not alarmed.
Stir in the peanuts until coated with caramel.
Pour the peanut-caramel mixture over the popcorn, which is still in it's large pot, and turn with a rubber spatula until nicely coated.
Turn out the popcorn mixture onto the baking sheets; using your spatula, spread it out evenly.
Crisp in the oven for 15 minutes, stirring once or twice; turn off the heat, but leave the caramel corn inside until cool, an hour or more; break up any chunks.