Mix soft butter with sugar until creamy.
Beat in eggs one by one.
Stir in vanilla.
In a separate bowl, mix flour, baking soda, salt and cinnamon.
Stir into creamy mixture.
Gently mix in oatmeal.
Chill dough in fridge for an hour.
Preheat oven to 375 degrees F (190 C).
Grease cookie sheets, or use waxed paper (no grease needed & easy clean up)
Place teaspoon size heaps about 2 inches apart on the cookie sheets.
Flatten each cookie with a fork dipped in sugar (oops, I forgot to do this)
Bake for 8-10 minutes, 10-15 minutes for a drier/crispy cookie.
Allow to cool on cookie sheet before transferring to a plate or tin.