These soft and chewy oatmeal cookie bars are everything you love about a classic oatmeal cookie — just easier and baked in one pan. They’re rich with brown sugar, cozy cinnamon, and a hint of molasses that gives them that deep, old-fashioned flavor. No scooping, no fuss — just press the dough into the pan and bake. And if you’ve got a KitchenAid Stand Mixer, this is the perfect recipe to let it shine — creaming the butter and sugar until light and fluffy makes all the difference in that soft, tender texture.
Finished with a simple vanilla icing that sets into a sweet crackly layer on top, these bars are perfect for sharing (or not). They slice beautifully, stay soft for days, and taste even better the next day — if they last that long.
Whip them up and get ready for your whole house to smell like fresh cinnamon-y oatmeal cookies!
Ingredients
Cookie Bars
- 1 cup (2 sticks) unsalted butter, room temperature
- 2 cups quick oats
- 2 cups + ¼ cup all-purpose flour
- 2 teaspoons baking soda
- 2 teaspoons cinnamon
- 1 teaspoon salt
- 1 cup granulated sugar
- 1 cup packed light brown sugar
- 2 large eggs, room temperature
- 2 teaspoons vanilla extract
- 2 tablespoons molasses
Vanilla Icing
- 1 cup powdered sugar, sifted
- 2–4 tablespoons whole milk
- ½ teaspoon vanilla extract
Instructions
Preheat oven to 350°F. Line a 9×13 baking pan with parchment paper or lightly grease it.
In a medium bowl, whisk together the quick oats, flour, baking soda, cinnamon, and salt. Set aside.
In a large mixing bowl, beat the room temperature butter with both sugars until light and creamy. This should take about 2–3 minutes. Don’t rush this step — creaming helps create that soft texture. If you have a Kitchenaid stand mixer, this process will be a breeze. If you don’t have one, a hand mixer will work as well, but you’ll definitely want an electric mixer for this job!
Add the eggs one at a time, mixing well after each addition. Stir in the vanilla and molasses until fully combined.
Gradually add the dry ingredients to the butter mixture. Mix just until combined and no dry streaks remain. Avoid overmixing.
Spread the dough evenly into the prepared 9×13 pan. The dough will be thick — use a spatula to press it into the corners.
Bake for 22–28 minutes, or until the edges are set and the center is lightly golden. The middle should look just set — don’t overbake if you want soft, chewy bars.
Cool completely in the pan before icing (about 1–2 hours).
Vanilla Icing
Whisk together powdered sugar, milk (start with 2 tablespoons), and vanilla until smooth and spreadable. Add more milk a little at a time if needed. If it becomes too thin, add more powdered sugar.
Spread over fully cooled bars. Let the icing set before slicing and serving.
Rumbly in my Tumbly 