I'd never been a fan of Peanut Brittle until I ate my mom's 60 year old famous recipe! This is the only Brittle I will eat! If you follow this recipe to the tee, you will be amazed of how it turns out. We used to double and triple this recipe at Christmas time to give as gifts and also to save plenty for ourselves!! This Peanut Brittle has a tendency to disappear fast!
Cook sugar, karo and 2 cups of butter until candy thermometer registers 238 degrees. Use medium heat. Secret: Make sure you only stir once in awhile. Otherwise, the Peanut Brittle will turn to sugar!
Stir in the peanuts and cook until golden brown (290 degrees on the candy thermometer).
Add the 2 Tablespoon butter and baking soda. (Do not be alarmed; it will foam up and change colors!)
Pour out on a well buttered cookie sheet and cool. Depending on how thick or thin you like it, 1 to 3 cookie sheets are used. I use a spatula to spread the mixture on the cookie sheet. Leave about 1 to 1 1/2 inches from the edge of the cookie sheet to prevent Brittle from running over.