Preheat oven to 350°. Line a large baking sheet with parchment paper, or spray it with nonstick spray. NOTE: This recipe makes 18 cookies, so you'll need to bake in batches or use two baking sheets.
In a medium bowl, mix the flour, cinnamon, baking soda, baking powder, and salt together; set aside.
In a large bowl, cream the butter, brown sugar and cane sugar together with a hand mixer or stand mixer, then add the milk and vanilla and stir to combine. Pour the dry ingredients into the wet, then mix to combine, being careful not to over-mix.
Stir the oats and raisins in by hand with a rubber spatula or spoon. This may take a minute, so be patient with this step.
Use your hands to roll the dough into balls, a slightly larger than golf ball size, then place them directly onto the baking sheet, ensuring they are at least 2 inches apart.
Bake the cookies for 11-13 minutes if you want a soft and chewy cookie (that's what I did). If you want a crispy cookie, press the cookie dough balls down to flatten them out, then bake them for 15 minutes. Remove them from the oven then leave the cookies on the baking sheet for at least 5 minutes before carefully transferring them to a cooling rack. Enjoy!