1. Heat oven to 350°F. Lightly grease cookie sheet or line with parchment paper.
2. Beat butter, brown sugar and granulated sugar until well blended in large mixer bowl. Add eggs and vanilla; beat until creamy. Stir together flour, baking soda, baking powder and salt; add alternately with buttermilk to butter mixture, beating well after each addition. Stir in small chocolate chips and nuts. Drop by level 1/4 cupfuls or heaping tablespoonfuls 2 inches apart onto prepared cookie sheet.
3. Bake 12 to 14 minutes or until golden brown. Cool slightly; remove from cookie sheet to wire rack. Cool completely. Frost with favorite vanilla frosting; garnish with colored sugar, if desired. Makes bout 36 (3-1/2 inch) sugar cookies.
*To sour milk: Use 1 tablespoon white vinegar plus milk to equal 1 cup.