In a medium microwavable bowl, add the butter and microwave until just melted. Stir in the peanut butter, maple syrup, and salt until smooth. Add 2 heaping cups of the crumbled popcorn and stir to combine.
Line a baking sheet or large plate with parchment. Use a small cookie scoop or spoon to scoop and form into rough balls and place on the parchment. Transfer to the freezer for at least 30 minutes to chill and harden.
Meanwhile, add the chocolate to a microwavable bowl and microwave in 20 second intervals, stirring after each time, until just melted.
Dip the peanut butter popcorn balls into the chocolate on one side, then sprinkle with remaining popcorn crumbles so they stick to the chocolate. Option to sprinkle with flaky salt. Place back onto the parchment and repeat with remaining balls.
Transfer back into the freezer for at least 30 minutes to chill. Enjoy right out of the freezer or let it sit out for a few minutes to soften.