Preheat your oven to 200 C / 400 F. Line a cookie sheet with parchment or grease it well.
Whisk or sift together the flour, salt and baking soda. Keep aside.
Beat together the butter , sugar and vanilla until light and fluffy.
Add the egg and beat until incorporated.
Add the vinegar and flour mixture , beat until a dough comes together. Its a soft and sticky dough.
Mix together the sugar and cinnamon for coating.
Make balls out of tablespoonfuls of cookie dough and roll in the cinnamon sugar mixture .
Place about 2 inches apart on your prepared cookie sheet (these spread quite a bit) and press down slightly.
Bake for 12 - 14 minutes until lightly brown.
Cool completely before storing .