Cream together the butter, egg, white sugar, brown sugar, and vanilla extract. The mixture will take on a pale brown color.
Mix the maple syrup into the egg and sugar mixture.
In separate bowl, mix together the flour, cinnamon, baking powder, baking soda, and kosher salt.
Fold in the flour mixture with a spatula until just incorporated. You don't want to overmix it.
Stir in the oats and raisins.
Chill the dough for 30 minutes. This will make it easier to scoop and roll the dough as well as prevent the cookies from spreading too much.
After the dough has chilled, roll the dough into 1.5 ounce balls (a little larger than golf ball sized - you'll get about 18) Preheat the oven to 350° while you do this.
Place the balls on a parchment paper lined baking sheet, I was able to fit 9 of them on the tray.
Bake for 12 minutes. The cookies will look a little soft but will set as they cool. Baking for 14 minutes may result in some tough cookies.