In a large mixing bowl, beat the butter with an electric mixer on medium speed for 30 seconds until blended and fluffy. Add the sugar and beat until well combined. Beat in the eggs, the cream of tartar, baking soda, vanilla and salt.

Beat in as much of the flour as you can with the mixer then fold in the remaining flour with a wooden spoon. Form the dough into a ball, kneading lightly only as much as needed to create a smooth, homogenous dough. Wrap in plastic wrap and chill in the refrigerator for at least 2 hours.

Preheat the oven to 375°F (190°C). Put a few tablespoons of granulated sugar in a small bowl.

Remove the cookie dough from the refrigerator and shape lightly into 1-inch (2 ½ cm) balls. Roll each ball in the sugar to coat and place the balls on ungreased cookie sheets spacing them 2 inches (5 cm) apart.

Bake for 9 to 12 minutes until spread, puffed, golden and just starting to brown around the edges. Remove from the oven and gently transfer the cookies to wire cooling racks.