Pop the popcorn and place it in a large grocery bag. Place the margarine, corn syrup, salt, and sugar in a large bowl and microwave it on High for 1 minute. Stir well. Microwave it on High until it reaches a boil and then microwave it on High for 2 minutes. Stir in baking soda, flavor and coloring (if desired). Pour over the popcorn and stir well, making sure the popcorn is well-coated. Roll the bag shut and microwave it on High for 90 seconds. Stir well, roll shut and microwave it for 60 on High. Roll the bag down (or tear it down) and leave open on its side. Microwave for 60 seconds on High. Pour out onto wax paper and spread it out to cool. When cool, break apart and remove any "old maids". Store in airtight container - if it lasts that long ! This fills one of the 5 qt. Ice cream buckets. For caramel corn: Use brown sugar instead of white and use vanilla or caramel flavoring. If you use the Lorann oils, one of the small bottles is the right amount of flavoring.