Pour the popcorn and slivered almonds into the buttered bowl.
In a medium pan, melt butter. Add the maple syrup and a dash of salt. Over medium heat, bring to a boil. Lower the heat and keep at a soft boil until a candy thermometer reads 300°F (about 15 minutes). Stir constantly.
Pour the maple syrup over the popcorn and slivered almonds and mix very well.
Spread the popcorn mixture onto the parchment paper. Let cool completely. Break apart and store in a covered bowl for 4 or 5 days.
Notes
This popcorn treat keeps well in an airtight container and is great for parties or a cozy movie night snack.