1 c. butter
1 lb. brown sugar
1 c. light corn syrup
1 (15 oz.) can sweetened condensed milk
1 tsp. vanilla

melt butter in saucepan. Add sugar. Stir in corn syrup; mix well. Gradually add milk, stirring constantly. Cook and stir over medium heat to firm ball stage, 12 to 15 minutes. Remove from heat and stir in vanilla. Pour in buttered 9"x9" pan. Cool and cut into squares.