Preheat oven to 350°F. Soak the raisins in the rum for at least 30 minutes, but up to 24 hours. The longer you let them soak the more flavor the raisins will soak up.
Cream together the butter, sugar and brown sugar until it is light and fluffy, about 3 minutes on medium speed. Add the eggs one at a time and mix until incorporated. Add vanilla extract.
In a separate bowl whisk together the flour, baking soda, salt, nutmeg, cinnamon, and oats. Add the dry mixture to the creamed butter/sugar. Mix until incorporated. Add the raisins and any of the rum that is left over, if any at all.
Scoop the cookies onto baking sheets lined with parchment. Bake for about 10 to 12 minutes. If you are making tiny cookies, they may need less time. I like to bake them until they are just set on top, but not too dark. This way they stay soft when you freeze them.
Let the cookies cool.