We got this yummy recipe from Lori B who taught the Little Chefs class at co-op during the Spring 2012 semester. Makes 16 cups.
4 quarts popped popcorn
1 cup butter, melted
2/3 cup sugar
1 tbsp cinnamon
Divide popcorn into 2 large bar pans. Combine butter, sugar and cinnamon in a bowl and pour over popcorn. Toss well to coat. Bake uncovered at 300° for 10 minutes. Cool and store in an airtight container.