Preheat oven to 250°F.
Combine seasoned salt, garlic powder, onion powder, smoked paprika, and pinch of chili powder or cayenne (if using) in a spice grinder. Pulse and grind into a fine powder.
Pop popcorn in a microwave, on the stovetop, or with an air popper. Place popped popcorn in a large bowl.
Melt butter in the microwave and stir in Worcestershire sauce until well combined.
Drizzle Worcestershire and butter mixture over the popcorn in the bowl.
Take a sheet pan and place it over the mouth of the bowl. Carefully pick up the bowl and sheet pan together and shake and toss vigorously to evenly coat the popcorn with the butter mixture.
Remove the sheet pan from on top of the bowl, sprinkle 1 TBSP of the powder over the popcorn. Replace the sheet pan over the bowl and shake again to evenly distribute.
Flip the sheet pan and bowl over so that the sheet pan is flat on the counter with the bowl upside down on top of it. Remove the bowl and spread the popcorn into an even layer.
Bake the popcorn for 5-7 minutes in the oven, stirring occasionally so that it all dries evenly.
Transfer popcorn back into the bowl and serve immediately.