Easy Peanut Butter Fudge

2 cups sugar
3/4 cup milk
4 T peanut butter
1 tsp vanilla
pinch salt

Boil sugar and milk without stirring until soft ball stage. Remove from heat. Let stand undisturbed until cool, then add salt, peanut butter, and vanilla. Beat with wooden spoon until stiff. Turn out into a greased 9 inch pan. Let sit until it hardens.