Prep the dry ingredients: In a large bowl, combine the popcorn, oats, cranberries, peanuts, and pepitas. Give it a good stir so everything is evenly distributed.
Get sticky! Pour the peanut butter and honey mixture over the dry ingredients. You can always melt the peanut butter in the microwave for easy mixing! Use a spoon or your hands to mix everything together until all the dry ingredients are evenly coated.
Press it down: Line a baking pan with parchment paper. Pour the mixture into the pan and use the back of a spoon or your hands to press it down firmly and evenly. You want to create a nice, flat surface.
Chill out: Cover the pan with plastic wrap and place it in the refrigerator for at least 1-2 hours. This will allow the bars to set and become firm.
Slice and enjoy! Once the bars are chilled, use a sharp knife to cut them into squares or rectangles.