Sourdough Iced Oatmeal Cookie Bars
These sourdough iced oatmeal cookie bars are like an easier version of oatmeal cream pies. Soft and chewy, made with sourdough discard and topped with vanilla icing, they're an easy cookie bar you'll make again and again.
Ingredients
Sourdough Oatmeal Cookie Bars
- ½ cup salted butter 1 stick, melted
- ¾ cup brown sugar packed
- ¼ cup white sugar
- 2 teaspoons vanilla extract
- 1 Tablespoon molasses do not use blackstrap molasses, use light or dark molasses
- 1 egg room temperature
- ½ cup sourdough discard
- 1 teaspoon baking soda
- 1 teaspoon ground cinnamon
- ½ salt
- ¾ cup all-purpose flour
- 2 cups quick oats
Vanilla Icing
- ⅔ cup powdered sugar
- ½ teaspoon vanilla extract
- 3-4 teaspoons milk
Instructions
Sourdough Oatmeal Cookie Bars
- Preheat oven to 350℉ (177℃). Line a 9x13 glass baking dish with parchment paper and set aside.
- In a large mixing bowl, combine melted butter, brown sugar, and white sugar. Add vanilla extract, molasses, egg, and sourdough discard. Mix to combine and scrape down the sides of the bowl.
- Add baking soda, ground cinnamon, and salt. Add flour and scrape down the sides of the bowl to combine. Add the oats and mix well.
- Pour the batter into the prepared baking dish and use a spatula to spread evenly to the edges and corners.
- Bake at 350℉ (177℃) for 22-24 minutes until browned all over and the middle is mostly set when you gently shake the pan. See note about baking time and testing doneness.
Key tip: Don't over bake! They secret to soft, chewy cookie bars is to slightly underbake them.
Vanilla Icing
- Once cookie bars are completely cooled, mix up the icing by combining powdered sugar, ½ teaspoon vanilla extract, and milk. Add 3 teaspoons of milk to start and if you want the icing a little thinner, add a 4th teaspoon.
- Spoon the icing onto cooled cookie bars and spread evenly. Cut the cookie bars before the icing cools and hardens to avoid cracks, see note. After slicing, allow the icing to cool and harden before serving.
Notes
Oats - Using quick oats for this recipe makes the bars softer and fluffier. You can use old fashioned oats as well, but pulse them in a blender or food processor first to break them up.
Molasses - Do not use blackstrap molasses for this recipe or your cookie bars may be bitter. Use light or dark molasses for baking. Grandma's Original Unsulphered Molasses is a good brand to use.
Baking - The cookie bars will get very brown all over from the molasses. It's not burnt, it just needs to be browned and the center not jiggle when you gently shake the pan.
To Slice - To cut cookie bars so the icing stays smooth and doesn't crack, slice them before the icing dries. Spoon on the icing and spread evenly. Use a large sharp knife to slice the cookie bars into squares, running the knife under warm water and drying with a clean dish towel between slices.
To Make Ahead - If wanting to serve these cookie bars the next day, don't add the icing right away or it will start to soak into the bars overnight. Make the cookie bars and allow to fully cool and cover the pan with plastic wrap. The next day add the icing and slice the bars, allowing the icing to harden before serving. This makes sure you're serving fresh, beautiful cookie bars!