Lightly grease a 9x12 inch cookie sheet and set aside.
In a 1 1/2 quart glass casserole dish, stir together the peanuts, sugar, corn syrup and salt, mixing well. Microwave for 4 minutes on high.
Remove dish carefully from microwave using pot holders as the dish will be hot, then stir again real well. Return dish to microwave and cook for an additional 4 minutes on high.
Remove dish from microwave and stir in margarine and vanilla, mixing well. Return dish to microwave and cook for an additional 2 minutes on high.
Remove dish from microwave. (This next step needs to be done quickly so have your lightly greased cookie sheet nearby.)
Now add the baking soda and quickly stir real well till light and foamy.
Immediately pour onto the lightly greased cookie sheet and spread it out to a thin layer. It will usually cover most of the cookie sheet. (Sometimes it helps to have someone spreading it out while you scrape out the dish). the bottom of the cookie sheet will be hot so be careful of where you set it.
Let mixture cool at room temperature. Once cool enough then break into small pieces and store in airtight container.
A few words of caution and wisdom:
Be careful making this if you have young children running around as this mixture is extremely hot.
Do not leave the spoon in the glass dish after you empty mixture out onto cookie sheet. It will stick to your glass dish and you will have a hard time getting it loose. (Experience talking)
Let water run until it is running hot before putting it in your glass dish to avoid the dish cracking or breaking. Then add the spoon to soak in the dish.
By Connie S. from Towanda, PA
Mix the first three ingredients and the salt.
Microwave on High for 4 minutes. Stir well and cook 5 more minutes. Add 1 tsp. vanilla and 1 tsp. butter.
Cook 1 minute and 45 seconds until it "browns." Add 1 tsp. soda and stir. (It will foam up.)
Pour onto a greased cookie sheet. (I prefer to use the Easy Release tin foil. It works great.)
8. Allow it to cool and harden. Break it up into pieces, then store it in an airtight container.
Be sure to make copies of this recipe because everyone who eats it will ask how you made it. It makes a great gift. It looks like you sweated over the stove to do this when it took only minutes in the microwave!
Source: Passed along to me from my mother-in-law.
By Sandy from Elon, NC
In a microwavable bowl, combine sugar, Karo syrup, peanuts and salt. Cook 7 to 8 minutes on high; stir after 4 minutes. Remove from microwave and add vanilla and butter. Cook 1 to 2 minutes longer, or until it starts to get a light brown in color. Remove and add baking soda. Stir and pour on a greased cookie sheet.
By Robin from Washington, IA