Preheat the oven to 350 F. In a medium bowl, whisk together flour, oats, salt, and baking soda. Beat butter with sugar in a large bowl until fluffy.
Add in egg and vanilla extract, and mix until smooth. Add in the flour mixture, and mix until a thick dough forms. Fold in dried cranberries.
Roll the cookie dough into balls, and place at least 2-inches apart onto ungreased baking sheets. Bake for 10-12 minutes.