Using a stand mixer, cream together butter, granulated sugar and brown sugar about 3-5 minutes.
Add eggs and vanilla. Mix until fully incorporated.
Add flour, baking soda and baking powder. Use a fork to work the baking powder and soda into the flour, then turn the mixer on low to incorporate fully.
Add rolled oats and chocolate chips (and raisins if using), again mix on low to incorporate.
Using a cookie scoop, place cookie dough on two cookie sheets. There should be room for 12 cookies per sheet. Place in the freezer for 20 minutes.
Preheat oven to 350˚F.
Bake cookies for 10-11 minutes, until just golden*
While cookies are baking, scoop remaining cookie dough onto parchment paper or a parchment lined container. Layer if needed with parchment between the layers. Place in freezer.
Once first batch of cookies are cooked, remove from oven and place onto a cooling rack.
After 2 minutes, remove baked cookies from cookie sheet and place on cooling rack to finish cooling.
Remove second batch of cookies once baked and cool as directed in the above steps.
Continue this process until all cookies are baked, or simply leave raw dough in the freezer to pop out and bake at a later date. Add 1 minute bake time to completely frozen cookie dough.
Store baked and cooled cookies in a sealed container for up to a week.