In medium bowl, stir together flour, baking soda, salt, 1/2 teaspoon pumpkin pie spice, and cream of tartar; set aside.
In large bowl, beat butter, 1 cup sugar and brown sugar on medium speed, scraping bowl often, until light and fluffy.
Add eggs and vanilla; mix well.
Add flour mixture. Blend on low speed, just until combined. Stir in toffee bits. Cover and refrigerate at least 1 hour.
Heat oven to 350 degrees F. Line baking pans with parchment paper. In small bowl, stir together 1/2 cup sugar and 1 tablespoons pumpkin pie spice.
Scoop chilled dough into 2 tablespoonful portions. Roll portions into balls. Roll dough balls in sugar mixture and place 3 inches apart on prepared pans.
Bake at 350 degrees F. for 9-11 minutes, until just set and puffy in centers. Remove from oven and cool 5 minutes on pan. Remove from pan and cool completely.
Repeat baking procedure with remaining dough.