Put sugar, syrup and butter in microwaveable dish and cook 2 minutes on high. Stir then cook 1 more minute on high. Add vanilla and baking soda, whip until frothy, then pour over popcorn in bag. Seal bag top by rolling down the top.

Microwave on high for 30 seconds. Shake the bag. Repeat by cooking for 30 seconds 2 to 3 more times, shaking the bag in between until popcorn is well coated. Put popcorn into bowl(s) toss the bag!