Line cookie sheet with waxed paper or foil.

Spoon 40 slightly-less-than-level measuring teaspoonfuls dulce de leche onto cookie sheet.

Freeze about 1 hour or until slightly firm (dollops will not freeze solid).

Heat oven to 400°F.

In large bowl, mix 1½ cups of the sugar, the butter, shortening and eggs.

Stir in flour, cream of tartar, baking soda and ¼ teaspoon of the salt.

Shape dough into 40 (1¼-inch) balls.

Press thumb into center of each cookie to make deep indentation, but do not press all the way to cookie sheet.

Place 1 dollop dulce de leche into center of each cookie, making sure to form dough around dollop to enclose.

(If necessary, work with lightly floured fingers so dough doesn’t stick.

) You may have to return dulce de leche dollops to freezer if they become too warm to work with.

In shallow bowl, mix remaining ¼ cup sugar, remaining ½ teaspoon salt and the cinnamon.

Roll balls in sugar mixture.

On ungreased cookie sheet, place balls 2 inches apart.

Bake 8 to 10 minutes or until set (centers will be soft).

Cool 2 minutes; remove from cookie sheet to cooling rack.

Store cooled cookies tightly covered up to 3 days.