Ingredients

• unsalted butter - 1 cup
• granulated sugar - 1 ½ cups
• brown sugar - ½ cup
• eggs - 2 large
• vanilla extract - 2 teaspoons
• all-purpose flour - 3 cups
• cream of tartar - 2 teaspoons
• baking soda - 1 teaspoon
• salt - ½ teaspoon
• ground cinnamon - 3 tablespoons
• granulated sugar for rolling - ¼ cup

Instructions

1. 1.

   Preheat the oven to 350°F (175°C).

2. 2.

   In a large bowl, cream together the butter, granulated sugar, and brown sugar until smooth.

3. 3.

   Beat in the eggs one at a time, then stir in the vanilla.

4. 4.

   In another bowl, combine the flour, cream of tartar, baking soda, and salt.

5. 5.

   Gradually blend the dry ingredients into the wet mixture.

6. 6.

   In a small bowl, mix the granulated sugar and cinnamon for rolling.

7. 7.

   Roll dough into balls about 1 inch in diameter, then roll each ball in the cinnamon sugar mixture.

8. 8.

   Place the coated balls on ungreased baking sheets, spaced about 2 inches apart.

9. 9.

   Bake for 8 to 10 minutes, or until the edges are set but the centers are still soft.

10. 10.

    Allow to cool on the baking sheet for a few minutes before transferring to wire racks to cool completely.