In a large bowl, cream together the butter, brown sugar, egg and vanilla until smooth. In a separate bowl, sift the flour, baking soda, cinnamon and salt together. Stir this into the butter/sugar mixture. Stir in the oats and chocolate chips.
Chill the dough for about 30 minutes
Drop by tablespoonfuls onto a parchment paper lined cookie sheet.
Bake for 10 to 12 minutes or until golden on the edges.
Remove from oven.
Let cool on the cookie sheet for about 5 minutes before transferring them onto a cooling rack.