Preheat your oven to 250 degrees F.
In a large pot (large enough to add the popcorn later and toss), melt the butter over medium heat. Stir in the brown sugar, honey, and salt. Bring to a boil, stirring constantly.
Once the mixture comes to a boil, boil for 4 minutes WITHOUT stirring. I adjust the heat to the lowest possible temperate that will just maintain a boil. This way, the mixture won’t burn.
After 4 minutes, remove the pot from the heat and stir in the vanilla and the baking soda. The mixture will get bubbly; this is normal.
Immediately add the popcorn and peanuts. Toss gently but thoroughly. If the mixture starts to firm up before you have thoroughly incorporated the popcorn, place the pot over low heat to soften the caramel mixture and finish mixing.
Place the popcorn mixture in a greased, 9×13 baking dish or other large, shallow pan and bake for 45 minutes, stirring every 15 minutes.
Remove from the oven and turn out onto parchment or wax paper and cool thoroughly, breaking apart any large clumps, if desired.
Store in an airtight container and enjoy!