In a medium bowl, stir together flour, baking powder, baking soda, salt and, if desired, nutmeg or cardamom; set aside.
In a large mixing bowl, beat butter with an electric mixer on medium to high speed for 30 seconds. Add sugar and beat until fluffy. Add egg and vanilla and beat well. Alternately add flour mixture and buttermilk, beating until well mixed. (Dough will be soft and sticky.) Cover and chill at least 5 hours or overnight or freeze for 3 to 4 hours.
Divide dough in half; return half to the refrigerator. On a well-floured surface, roll into a 10x5-inch rectangle. With a sharp knife, cut rectangle into twenty 5x1/2-inch strips. Place half of the strips on a baking sheet or tray and place in the refrigerator while shaping and baking the first 10 strips. Roll each strip into a 10-inch-long rope. Shape each rope into a loop, crossing 1-1/2 inches from ends. Twist rope at crossing point. Lift loop over to touch ends and seal, forming a pretzel shape. (Or fold each 10-inch-long rope in half and twist 3 times; seal ends.) Place cookies 2 inches apart on ungreased cookie sheets.
Bake in a 425 degree F oven 5 to 7 minutes or until cookie bottoms are light brown (tops will be pale). Remove from cookie sheets and cool slightly on wire racks. Repeat with remaining dough strips and dough. Serve warm with softened butter, if desired or serve cool. Makes 40 cookies.
To make 1 cup sour milk, place 1 tablespoon lemon juice or vinegar in a glass measuring cup. Add enough milk to make 1 cup total liquid; stir. Let stand for 5 minutes before using.