Bring the butter, sugar, salt and corn syrup to a boil - keep bubbling over med heat until it hits the softball stage (240 degrees - use a candy thermometer and adjust for your altitude)
Add the sweetened condensed milk and boil 1 more min - let it cool a few mins so it doesn't shrink the popcorn.
add the vanilla, apple cider vinegar and rum extract and stir
pour out 1 Tbsp to use in the topping - then depending on which style of popcorn you are making add the sauce to the popcorn and stir
Butterbeer "foam" topping
add the heavy cream to the chocolate in a microwave safe bowl and heat - I use the "melt chocolate button" but you can always heat for 1 min at 60% power, stir and add 30 seconds more until its melted
add the 1 Tbsp held over from the popcorn sauce and stir
add a few drops of white food dye and stir
pour this white chocolate mixture into a piping bag to easily top the popcorn
popcorn balls
I do 1 - 1 1/2 batches of air popped popcorn (13+ cups) for this to keep them gooier and sticking together
spread the popcorn out and let it start too cool
spray your hands with non stick spray and portion it out into 8 sections and ball up.
Continue to check back and ball and turn until they cool enough that they stay in their ball forms
add the topping, let set and serve!
gooey caramel popcorn
I do 2-3 batches of air popped popcorn for this - 2 batches is still fairly gooey, 3 is better for sharing
add the topping and serve immediately
crunchy caramel popcorn
I go for the full 3 batches of air popped popcorn for this
stir and evenly coat the popcorn as best you can
preheat your oven to 250 - spread it out in a pan and place in the oven and bake for like 25-30 mins, stirring occasionally
let cool on counter slightly and add the white chocolate topping. Let set completely and break apart