1Combine sugar, milk, and cornstarch together and cook to a rolling boil. Once it starts boiling, cook for EXACTLY 3 minutes. Remove from heat, stir in peanaut butter and vanilla extract. Stir until completely smooth and starts to get thick in pan.
Pour in buttered 9" pan (8" for thicker fudge). Put in fridge to cool. Cut in squares, put in container and ENJOY!!!