From my collection of handwritten recipes 1970's.
Note: Prep time and cook time are not given. It's been far too long since I made this, so I forgot the exact times and the yield. I've just written in numbers so don't go by them if you try this.
Use heavy skillet with a tight lid to boil sugar, water, and karo (400*F.) until it spins a thread 1 foot long. Add raw spanish peanuts and vanilla. Stir gently until peanuts crack or pop. Stir until light beige, not gold or tan. Remove from heat. Add 2 scant teaspoons baking soda. Stir quickly and pour onto greased cookie sheet.