Peanut Butter Fudge

1/2 cup butter
2 cups brown sugar
1/2 cup milk
1 cup peanut butter
1 tsp vanilla
3 cups powdered sugar
1/3 cup finely chopped salted peanuts

Prepare an 8″ pan by lining with foil and coating with butter. Melt butter in a saucepan. Add brown sugar and milk. Bring to a boil and boil for exactly 2 minutes, stirring constantly. Remove from heat and add peanut butter and vanilla. Measure powdered sugar into a large bowl and pour hot mixture over the top. Beat till smooth. Pour into prepared pan. Chill till set. Cut into small squares.