Heat oven to 350º. Lightly oil two sheet pans or line each with parchment or a nonstick baking mat. Place a kitchen towel on your work surface. Lightly mist two spatulas with cooking spray.

Place the metal bowl into the oven while you make the caramel.

Combine the water, sugars, corn syrup and butter in a large saucepan set over medium-high heat. Cook, stirring to dissolve the sugar, until the mixture reaches 270ºF. It will bubble considerably.

While the syrup is cooking, remove the bowl from the oven. Spread the peanuts on a small sheet pan and place in the oven. Spray the mixing bowl with cooking spray and place onto the towel. Pour most of the popcorn, about 8 cups, into the  mixing bowl. Make a well in the center.

When the caramel reaches 300ºF, remove from heat and immediately stir in the baking soda and salt, taking care as the caramel will foam up. Remove the peanuts from the oven and toss into the caramel. Immediately pour the caramel into the well and over the popcorn in the mixing bowl, avoiding the sides of the bowl as much as possible. Cover with the remaining popcorn.

Using the two spatulas, quickly toss the popcorn and caramel together, drawing the popcorn from the edges into the center. Continue to stir and toss to coat as much popcorn as possible.

Pour the hot mixture onto one of the prepared sheet pans. Using your hands, being extra careful because the mixture is quite hot, break up any of the larger clumps of popcorn. As you work, transfer half of the coated popcorn to the second sheet pan. Let the caramel popcorn set until cooled and hardened.

Store in a covered container at room temperature. Well-coated popcorn should remain fresh for about 3 days (if you don’t eat it all up before then).