Combine first four ingredients in an 8 cup glass measure or large bowl. Cook on HIGH 7 to 8 minutes.
Stir well after 4 minutes.
Add butter and vanilla and blend well.
Cook on HIGH 1 minute. Peanuts will be lightly browned and syrup very hot.
Add baking soda and stir until light and foamy.
Pour mixture onto lightly greased cookie sheet.
When cool, break into small pieces and store in air-tight container.
If roasted, salted peanuts are used, omit salt and add peanuts after first 4 min. of cooking