Oatmeal isn’t just a tasty breakfast food. It gives these chocolate chip cookies lots of oat flavor and a chewy texture.
Adjust oven rack to middle position and heat oven to 375 degrees. Line rimmed baking sheet with parchment paper.
In medium bowl, whisk together flour, salt, and baking soda.
In large bowl, whisk together brown sugar, oil, melted butter, and cinnamon. Add egg and vanilla and whisk until mixture is smooth.
Add flour mixture to sugar mixture and use rubber spatula to stir until fully combined, about 1 minute. Add oats and chocolate chips and stir until evenly distributed.
Use 1-tablespoon measuring spoon to drop dough onto parchment-lined baking sheet in 12 mounds (about 2 heaping tablespoons each). Leave space between mounds. Wet your hand lightly, then use your damp hand to gently flatten each mound into 2-inch-wide circle.
Place baking sheet in oven. Bake cookies until edges are set and lightly browned but centers are still soft, 8 to 10 minutes.
Use oven mitts to remove baking sheet from oven (ask an adult for help). Place baking sheet on cooling rack and let cookies cool on baking sheet for 10 minutes.
Butter can be melted in a small saucepan on the stove (use medium-low heat), but we think the microwave is easier.
Rolled oats (also called old-fashioned or regular oats) are whole oats that have been steamed and then rolled. If these same oats are rolled very thinly, they are called quick oats because they cook, well, more quickly. Instant oats are cooked and then dehydrated, so they don’t need any more cooking, just hot water. Not all brands of rolled oats are the same—some are denser than others (they weigh more). For these cookies, we had the best luck using Quaker old-fashioned rolled oats. (We found that cookies made with Bob’s Red Mill old-fashioned rolled oats spread out a bit more in the oven.) Don’t use quick, instant, or extra-thick rolled oats in this recipe.