Microwave Caramel Popcorn

1 bag microwave popcorn, popped

1C mixed nuts (optional)
2/3C sugar
1/3C corn syrup
1/3C butter
1/4t salt
1t vanilla
1/4t baking soda

Lightly grease a 4 quart microproof bowl, add popcorn and nuts, toss to mix
Cover heatproof counter with 18-24 inches of waxed paper
Mix sugar, corn syrup, butter and salt in 4C glass measure and micro on high for 3 minutes or until mixture boils, stir after each minute
Micro on high an additional 3-5 minutes or until mixture turns light brown on top
Stir in vanilla and soda, and quickly pour over popcorn
Toss to coat
Micro popcorn on high for 2 minutes, stirring WELL every 30 seconds
Turn onto waxed paper to cool then break into pieces