14-16 cups plain popped popcorn (I use an air-popper and make 1 ½ batches)
½ cup sugar
½ cup light corn syrup
¼ cup butter (no substitutions), cut into chunks
Dash salt
2 ounces unsweetened baking chocolate, chopped
1 teaspoon vanilla
Nonstick cooking spray
Preheat oven to 300°.
Place popped popcorn in a large roasting pan or other extra-large baking pan coated with cooking spray. (If you do not have an extra-large pan, you can use 2 9x13-inch baking pans and divide the popcorn evenly between them.) Bake at 300° for 15 minutes, stirring every 5 minutes; this removes extra moisture from the popcorn so the finished product will be crisp.
Combine sugar, corn syrup, butter, salt, and chocolate in a 2-cup microwave-safe measure or small microwave-safe bowl. Microwave on High power 2 minutes or until boiling, stirring after 1 minute. Watch carefully unless you want to create a chocolate volcano in your microwave! Remove from microwave and stir in vanilla.
Carefully pour the very warm chocolate mixture over the popcorn and toss gently to coat using a large spoon or spatula. Serve immediately or allow to cool in the pan. Makes about 14 cups. Which sounds like a lot but is in fact usually just barely enough.