Preheat oven to 350F. Lightly coat 2 baking sheets with cooking spray or line them with parchment paper.
In a food processor, pulse 2cups flour, salt, baking powder, baking soda and cream of tartar until combined.
Add the butter and pulse until butter reduces to pea-size pieces. Transfer to a large bowl.
Grind the pecans in food processor until they start to clump together. Stir pecans into butter mixture, add maple syrup and sour cream and mix until just combined. Do not overmix. The dough is rather sticky at this stage.
Place remaining 1cup of flour on a plate. Scoop 2" balls of dough into the floor and roll to coat with flour.
Arrange the dough balls 2" apart on prepared baking sheets and bake for 24~26 minutes or until the edges turn golden.