Cook popcorn using your desired method. These days I air pop my popcorn, but you can also do it in a heavy pot with oil.
In a small pot combine butter, syrup, and spices over medium low heat. Heat until the mixture is bubbling heavily, maybe 3-4 minutes. Stir occasionally. Remove from heat once the sauce is combined, bubbling, and slightly thickened.
Let the sauce cool briefly and spread popcorn out in an even layer on a baking sheet lined with parchment paper. Drizzle sauce over the popcorn evenly.
Let popcorn cool briefly so sauce can stick to the popcorn. It will be a bit wet on the popcorn, but really tasty.