Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   8      cups          popped popcorn (about 1/3 to 1/2 cup unpopped)
    3/4   cup           packed brown sugar
    1/3   cup           butter
   3      tablespoons   light-color corn syrup
    1/4   teaspoon      baking soda
    1/4   teaspoon      vanilla
                        Nonstick spray coating

Preparation:

Spray an 18x12x2 inch baking pan with nonstick spray. Remove unpopped kernels from popped corn. Place popcorn in pan; keep warm in a 300 F oven. Butter sides of heavy 1 1/2-quart saucepan. Add brown sugar, butter and corn syrup. Clip candy thermometer to side of pan. Cook and stir over medium heat to 255 F, hard-ball stage (about 4 minutes). Remove saucepan from heat. Stir in baking soda and vanilla; pour over popcorn. Stir gently to coat. Bake in a 300 F oven for 15 minutes. Stir and bake 5 minutes more. Remove from oven; spread onto a large piece of foil and cool completely. Break into clusters.