With an electric mixer, beat the margarine and sugar until light and fluffy. Add the eggs, one at a time, beating for at least 30 seconds after each egg -- again, light and fluffy.
Thoroughly mix together the flour, salt, cream of tartar and baking powder. Add to the batter one half cup at a time, stirring until blended.
Chill the dough until it is thick enough to scoop, then scoop out 24 balls of dough and put them on plastic wrap lined plates. Continue to chill the dough balls for at least another hour or until ready to bake.
Preheat oven to 375 degrees F. Combine remaining 2 tablespoons sugar and cinnamon.
Mix together sugar and cinnamon and roll chilled dough balls in cinnamon mixture. Place 3 inches apart on parchment lined baking sheets. Bake for 12-14 minutes or until edges are browned. The cookies should puff up in the oven, then flatten as they cool.
Makes 2 dozen cookies.