- With the rack in the middle position, preheat the oven to 375°F (190°C). Line two baking sheets with silicone mats or parchment paper.
- In a bowl, combine the oats, flour, raisins, if desired, spices, baking soda and salt (see note).
- In another bowl, cream the butter, brown sugar, oil and vanilla with an electric mixer. Add the egg and whisk until smooth. With the machine running on low speed, or using a wooden spoon, add the dry ingredients.
- Using an ice cream scoop, form the mixture into 12 balls and spread out on the baking sheets. Press the balls down until ¾ inch (2 cm) thick.
- Bake one sheet at a time for 10 minutes or until the cookies are lightly golden. Let cool on the baking sheets before handling the cookies.
Adding raisins increases the quantity of sugar in the recipe.