• Preheat the oven to 400°F. Lightly grease (or line with parchment) two baking sheets.

MAKE THE COOKIE DOUGH:

• In a large bowl, use an electric mixer to beat together the sugar and shortening until smooth. Then add the eggs, again beating until smooth. Beat in the vanilla. In a separate bowl, whisk together the flour, cream of tartar, baking soda and salt. Add the flour mixture to the wet slowly and mix just until combined. (If you over-mix, the cookies may turn out a little tough.) Stir in the chips.

SHAPE THE COOKIES:

• Place the cinnamon sugar in low, flat bowl. Roll the dough into smallish (heaping teaspoonful) balls and put into the bowl with the sugar. You can do about 6 balls at a time, roll them in the sugar and then place them on the prepared baking sheet. Leave about 1½ inches between each cookie (they do spread). Using the bottom of a glass, flatten each cookie until it's about ¼-inch-thick and 1½-inches in diameter. Repeat until you've used up all of the dough.
• Bake the cookies for 10 or 11 minutes. They should be set and just starting to turn golden. Remove the cookies from the oven and cool on a rack. As they're cooling, very lightly dust them with ground cinnamon (a fine sieve or tea strainer both work well.)