Preheat oven to 350°F (175°C).
Cream the butter and sugar together.
Add the eggs and beat in well.
Sift together the flour, cream of tartar, baking soda, salt and Speculaas spice mix.
Stir the flour mixture into the butter, sugar and egg mixture thoroughly.
Chill the dough for 30 to 60 minutes.
Meanwhile in a small bowl, mix together the 2 tablespoons of sugar and half teaspoon of Speculaas spice mix.
When the dough has chilled, roll it into one inch balls.
Roll each ball in the mixture of sugar and Speculaas spice mix.
Place two inches apart on ungreased baking sheets.
Bake 8 to 10 minutes until lightly golden.
Take the baking sheets out of the oven and allow the cookies to sit for a minute or two to firm up.
Carefully remove the cookies from the baking sheets and cool on wire racks.
Store in an airtight container at room temperature.