In a medium bowl, whisk together the flour, cream of tartar, baking soda and salt. Set aside.
In a large bowl, beat the dairy free butter, granulated sugar and brown sugar for 2 minutes until light and fluffy. Beat in the egg, egg yolk and vanilla until smooth.
Add the dry ingredients and mix on low speed just until combined. Cover and chill the dough for at least 1 hour, which prevents spreading and gives you thick, chewy centers.
Preheat the oven to 350°F and line two baking sheets with parchment paper. In a small bowl, stir together the sugar and cinnamon for rolling.
Roll the dough into 1 1/2 tablespoon balls and roll each one generously in the cinnamon sugar. Place them about 3 inches apart on the baking sheets.
Bake for 10-11 minutes, until the edges are set and the centers look puffy and slightly underdone. The tops will crinkle beautifully as they cool.Let the cookies rest on the sheet for 5 minutes, then transfer them to a wire rack.