Prepare the filling:
In a medium bowl, mix together softened butter, brown sugar, and cinnamon until smooth. Set aside.

Make the dough:
In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.
Add in the eggs, one at a time, and vanilla extract. Beat until fully incorporated.
In a separate bowl, whisk together the flour, baking soda, salt, and cream of tartar. Gradually add the dry ingredients to the wet ingredients and mix until a dough forms.

Roll the dough:
On a lightly floured surface, roll out the dough into a rectangle (about 1/4 inch thick).
Spread the prepared cinnamon filling evenly over the dough.

Form the cookies:
Carefully roll the dough up like a log, starting from the long edge. Once rolled, slice the dough into 1/2-inch thick rounds.

Coat with cinnamon sugar:
In a small bowl, mix together the sugar and cinnamon for rolling. Roll each cookie dough slice in the cinnamon sugar mixture, coating both sides.

Bake:
Preheat your oven to 350°F (175°C). Place the cinnamon roll cookies on a baking sheet lined with parchment paper, spaced about 2 inches apart.
Bake for 8-10 minutes, or until the cookies are golden around the edges.

Cool and enjoy:
Let the cookies cool on a wire rack before serving.