Preheat oven to 350°F and prepare cookie sheets with parchment paper.
In a medium bowl, measure out the raisins and pour 2 cups of water over them (ensuring that all the raisins are under the water). Let them sit in the bowl of water until ready to add to the cookie dough.
Place the butter, sugar, and light brown sugar into the bowl of an electric mixer.
Cream the softened butter, sugar, and light brown sugar together on medium speed (speed 4 for a Kitchen Aid) for 4 minutes until light and fluffy.
Next, scrape down the sides of the bowl and add one egg at a time mixing until fully combined and scraping down the sides of the bowl after each egg.
Add the vanilla and mix until combined.
In a separate bowl, measure the flour, salt, baking soda, cinnamon, and oats. Whisk together with either a whisk or fork.
Add the dry ingredients to the mixing bowl and mix on a low speed until the flour is almost completely mixed in (some streaks of flour remaining).
Next, strain the water out of the raisins and pat dry with some paper towel ensure no extra water remains.
Finally, add the drained raisins to the cookie dough and continue mixing on low until the raisins are evenly distributed. Be careful NOT to overmix!
Using a cookie scoop, scoop the cookie dough and place 1 inch apart from each other on the parchment lined cookie sheets.
Place the trays in the oven and bake for 10-15 minutes or until the edges are golden brown.
Immediately after the cookies come out of the oven, round them out with either a cookie circle cutter or something with a round rim that is heat safe (like a drinking glass or small glass bowl).
Let the cookies cool for 5-7 minutes on the cookie sheet, then transfer the cookies to a wire rack to continue cooling. Enjoy!