Don't preheat the oven yet because the cookies require some chilling.
In a medium bowl, stir together flour, baking soda, cinnamon, salt, and oats. In the bowl of a stand mixer, beat the butter and both sugars together until thoroughly blended. Beat in the eggs, one at a time, then add the vanilla. Add the flour/oat mixture and mix on low speed until everything comes together. Stir in the raisins.
Divide the dough into 12 equal portions and set them on a baking sheet or a couple of plates. Cover with plastic wrap and chill slightly until dough is just firm enough to handle, then shape each portion into a neat mount by rolling into a very compact ball and pressing down slightly. Continue chilling until dough mounds are very firm.
When you are ready to bake, preheat the oven to 350 degrees. Divide the dough balls between two parchment lined sheets and bake for 18-22 minutes, rotating the pans halfway through the baking time. Or bake one sheet at a time. Remove the pans from the oven, and allow the cookies to cool on the baking sheets before transferring them to a wire rack to cool completely.