Place soft butter and both sugars in a bowl. Beat them together until the mixture looks light. This should take about five minutes of mixing.

Add the eggs and vanilla to the creamed butter. Mix on medium speed until combined and smooth. Scrape the sides of the bowl with a spatula.

Sift the flour, baking soda, and cinnamon together. Slowly add this dry mix to the wet batter. Turn the mixer to a very low speed.

Fold in the oats and raisins by hand now. Stir until everything is just combined together. Do not overmix the dough at this stage.

Scoop the dough into round balls with a spoon. Place them two inches apart on the baking sheet. Flatten them slightly with your damp fingers.

Bake the cookies for twelve to fifteen minutes. They should look golden brown around the edges. The centers will still look a little soft.

Let the cookies cool on the pan for five minutes. Move them to a wire rack after that. Allow them to cool completely before eating them.