Cream sugar & margarine well before adding the egg and vanilla. Add the buttermilk & baking soda. Mix well. Slowly add the baking powder and flour to the creamed mixture. Cover dough with plastic wrap and chill for 2 hours.
Preheat oven to 350 degrees F while rolling out dough on well floured counter. Dough should be about rolled out to 1/2 of an inch thick. Use a round shaped cookie cutter or top side of a drinking glass that has been dipped in flour to cut cookies.
Place 12 cookies on a nonstick cookie sheet and bake 5 to 7 minutes. Place on rack and let cool.