Place the sugar & butter in a large mixing bowl and beat with an electric mixer on medium-high speed until combined.
Add the egg, molasses, vinegar, and vanilla extract and beat on medium-low speed until fully combined.
In a separate bowl, mix the flour, baking soda, salt, and gingerbread spice mix until well combined.
Add the dry ingredients to the molasses mixture and mix on low speed just until combined into a soft dough.
Cover the bowl and chill the dough for at least 3 hours or overnight.
Preheat the oven to 350°F (175°C).
Divide the dough in half and roll each half to ¼ inch thickness on a lightly floured surface.
Cut out cookies and place them on lined baking sheets about 1 inch apart.
Bake medium cookies for 8-10 minutes, large cookies for 12-14 minutes, and small cookies for 6-8 minutes.
Cool the cookies on the baking sheet for a couple of minutes, then transfer to a wire rack to cool completely before decorating.