Preheat the oven to 350 F. In a medium bowl, whisk together flour, oats, salt, and baking soda. In a large bowl, combine butter with both sugars until fluffy. Add in the egg and vanilla extract and mix until smooth.
Add in the flour mixture, and mix until it is fully combined. Roll the cookie dough into ovals, and place them onto a large ungreased baking sheet, and bake for 10-12 minutes. Let cool completely.
Place the frosting into a piping bag, and decorate each cookie in a football pattern.