Preheat oven to 250°F.
Pour popcorn and peanuts into a very large bowl (or two large mixing bowls and set aside.
Melt butter in a (medium) saucepan over medium-high heat.
Stir in the sugar, corn syrup and salt until fully incorporated.
Bring mixture to a boil, frequently stirring.
Once mixture has come to a boil stop stirring and continue to boil for about 5 minutes.
Remove saucepan from heat and carefully stir in baking soda (the mixture will vigorously boil).
Stir in the cream and vanilla and pour the caramel sauce over the popcorn. Fold together until mostly combined.
Evenly spread the caramel popcorn onto two parchment lined baking sheets, in a single layer.
Bake for about an hour, removing the mixture from the oven every 15 minutes to stir.
Allow caramel corn to cool completely before breaking up into pieces.
Toss together with cheddar popcorn until fully combined. Serve.