Heat your oven to 350 degrees and line 2 cookie sheets with parchment paper.
In a medium bowl, whisk the flour, oats, cinnamon, baking soda and salt.
In a separate large bowl, beat the butter and sugars using an electric hand mixer until fluffy. Add the vanilla, vinegar and milk and beat again.
Stir the dry ingredients into the wet ingredients along with the milk. I find it's easiest to use your hands as the dough is thick.
Stir in the raisins.
Drop onto the prepared pan by heaping 1 Tbsp balls. Press out JUST slightly, you want the balls higher than they are round.
Bake until the edges are VERY lightly brown, about 12-13 mins. The cookies firm up on the pan A LOT.
Cool on the pan for 5-10 minutes until set and then transfer to a wire rack to cool completely.
DEVOUR
Video
Notes
*If you use a GF 1:1 flour, I recommend removing about 2 Tbsp as I found it works better this way. You may need to play with this depending on your flour.