Prepare the Cookie Dough:

1. Preheat the Oven:
   Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper or silicone baking mats.

2. Cream the Butter and Sugars:
   In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy, about 2-3 minutes with an electric mixer.

3. Add the Eggs and Vanilla:
   Beat in the eggs, one at a time, and then stir in the vanilla extract.

4. Combine the Dry Ingredients:
   In a separate bowl, whisk together the flour, cinnamon, baking soda, and salt.

5. Mix in the Oats:
   Gradually add the dry ingredients to the wet ingredients and mix until just combined. Stir in the oats until evenly distributed.

6. Add the Raisins:
   Fold in the raisins, making sure they are spread throughout the dough.

Bake the Cookies:

1. Scoop the Dough:
   Use a cookie scoop or tablespoon to drop rounded balls of dough (about 1 ½ inches in size) onto the prepared baking sheets. Leave about 2 inches between each cookie to allow for spreading.

2. Bake the Cookies:
   Bake for 10-12 minutes, or until the edges are golden brown but the centers are still soft. The cookies will firm up as they cool.

3. Cool:
   Let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.

Serve and Enjoy:

1. Serve:
   Once cooled, serve these chewy oatmeal raisin cookies with a glass of milk, or store them in an airtight container at room temperature for up to a week.