2Add pop corn to a large (about a 3-4 quart size) microwave safe bowl. Add peanuts to the popcorn at this time if you want them.
3In a 2 quart measuring cup, or a microwave safe bowl, heat the butter until melted.
4Stir in sugar and corn syrup and microwave on high for 3-4 minutes.
5Remove from microwave and stir in the vanilla and baking soda until blended. Drizzle over popcorn, stirring to mixing well. Microwave the bowl of popcorn for about 2-3 minutes, stirring every minute or so to coat the popcorn evenly.
6Pour the caramel corn into a oblong cake pan or a jelly roll pan that has been lined with non-stick foil. Or you can use waxed paper that has been coated with butter or a spray coating. Cool the popcorn completely and then break apart the caramel corn. Store in an container.