Preheat oven to 350 degrees and line baking sheets with parchment paper.
Add butter and sugars to a mixing bowl or bowl of stand mixer, and beat until light and fluffly (about 2 minutes).
Add eggs, one at a time, mixing between each. Add vanilla with the last egg and mix well.
In a separate mixing bowl, whisk together oats, flour, baking soda, salt and spices until well combined; add to butter mixture and mix on low speed just until combined.
Stir in chocolate chips and raisins just until combined.
Scoop out dough onto cookie sheets leaving room between as they will spread out. Bake at 350 degrees for 9 to 11 minutes, just until edges begin to brown.
Remove from oven and transfer to a cooling rack to cool. Drizzle with melted chocolate if desired.
Notes
Use a large cookie scoop for nice big cookies. It should hold about 3 to 3 1/2 tabespoons of dough.Don't overbake. Bake just until edges and bottom of cookie are golden.