Preheat your oven to 350 degrees Fahrenheit. Line a baking sheet with parchment paper and set aside.
In a medium bowl, combine the flour, baking soda, cinnamon and salt. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, cream together the butter and brown sugar. Whisk in the maple syrup, milk and vanilla extract. Add the egg and stir to combine. (You can also use a hand mixer.)
Fold in the rolled oats. Mix in 1/2 of the flour mixture until no clumps remain, then mix in the remaining flour mixture.
Fold in the raisins.
Use an ice cream scoop to scoop out 10 cookies and flatten them slightly with the back of a spoon.
Bake the cookies for 12 to 14 minutes, or until they are slightly golden on the bottom. They will be a little soft when they come out of the oven, but will firm up as they cool.
Transfer the cookies to a cooling rack and allow them to cool before enjoying.