Okay...this is a super-secret family recipe, but I'll share it! We always make tons of this during the holidays, but don't try to make it on a humid day.
Pop two bags of microwave popcorn...I use the unsalted, no butter, but you can use whatever you like. Add 1 cup EACH pecan halves and whole almonds. Put it in a BIG bowl.
In a medium saucepan melt two sticks real butter, add 1 cup light Karo syrup, 3/4 cup white sugar and stir until dissolved. Cook to soft ball stage without stirring (I always use a candy thermometer for this part...you don't want it too hard), remove from heat and and stir in 1 Tbsp. vanilla extract. Pour over popcorn/nut mixture and spread on parchment or waxed paper. After it cools a bit I break it apart. This stays soft and chewy, gooey and it's so good!