1/4 c. butter
1 c. brown sugar
1 c. granulated sugar
3/4 c. sour cream
1 tsp. vanilla
1/2 chopped nuts

Melt butter in heavy saucepan, add brown sugar and heat to boiling. Add granulated sugar and sour cream. Cook over low heat, stirring until sugar dissolves, to soft ball stage (235°F). Cool at room temperature, without stirring, until lukewarm (110°F). Beat until mixture holds its shape. Add vanilla and nuts, quickly spread in greased pan. Cool and cut in squares.