I turned a browned butter blondie idea into iced oatmeal cookie bars that began as a kitchen experiment and became my favorite Oatmeal Cookie Bars.

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I can’t stop thinking about these Iced Oatmeal Cookies, they started as a browned butter blondie and somehow got even better with a simple hit of vanilla extract. They come out moist and chewy, with just enough chew to make you pause and wonder how one pan could taste this grown up.

I call them my Dessert Bar Recipe when I need something that travels well, but honestly they disappear too fast. They’re the kind of treat that makes you promise to only have one, and then break that promise five minutes later, so yeah, you been warned.

Ingredients

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Browned butter: nutty, toasty fat that deepens flavor and adds chew, not just fat.
Brown sugar: provides molasses notes, moisture and chew, makes bars sweet and kinda cozy.
Rolled oats: whole grain fiber and texture, slows digestion and keeps you fuller longer.
All purpose flour: binds everything, adds structure but more carbs less fiber than oats.
Eggs: supply protein, moisture and help hold bars together, they add richness too.
Raisins or chocolate chips: optional sweetness burst, fruit adds natural sugars, chocolate adds indulgence.
Powdered sugar glaze: simple sweet finish, adds sugary shine and slight vanilla aroma, not heavy.

Ingredient Quantities

1 cup (2 sticks) unsalted butter, browned and cooled

1 cup packed light brown sugar

1/2 cup granulated sugar

2 large eggs, room temp

2 teaspoons vanilla extract

1 1/2 cups all purpose flour

1 teaspoon baking soda

1/2 teaspoon fine sea salt

3 cups old fashioned rolled oats

1 teaspoon ground cinnamon

1/4 teaspoon ground nutmeg

1 cup raisins or chocolate chips, optional

1/2 cup chopped pecans or walnuts, optional

1 1/2 cups powdered sugar (for glaze)

2 to 3 tablespoons milk or cream (for glaze)

1 teaspoon vanilla extract (for glaze)

Pinch of salt (for glaze)

How to Make this

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1. Preheat oven to 350°F (175°C). Line a 9×13 pan with parchment paper leaving an overhang or spray it well so bars come out easy.

2. Brown 1 cup (2 sticks) unsalted butter in a light colored saucepan over medium heat, swirling often until the milk solids turn golden brown and it smells nutty, about 5 to 7 minutes. Remove from heat and let cool until warm but not hot so you dont scramble the eggs.

3. In a large bowl mix 1 cup packed light brown sugar and 1/2 cup granulated sugar with the cooled browned butter until mostly smooth. Add 2 large room temp eggs one at a time, mixing after each, then stir in 2 teaspoons vanilla extract.

4. In another bowl whisk together 1 1/2 cups all purpose flour, 1 teaspoon baking soda, 1/2 teaspoon fine sea salt, 1 teaspoon ground cinnamon and 1/4 teaspoon ground nutmeg.

5. Add the dry mix to the wet and stir just until combined, dont overmix. Then fold in 3 cups old fashioned rolled oats and if using, fold in 1 cup raisins or chocolate chips and 1/2 cup chopped pecans or walnuts.

6. Scrape the batter into the prepared pan and press it into an even layer with a spatula or the back of a spoon. A slightly damp spatula helps get a smooth top without sticking.

7. Bake for 20 to 25 minutes until the edges are golden and the center is set but still a little soft. Rotate the pan halfway through if your oven bakes unevenly.

8. Cool the bars completely in the pan on a wire rack, at least 45 minutes to an hour. If you glaze while warm the icing will run off and get soggy.

9. Make the glaze by whisking 1 1/2 cups powdered sugar with 2 to 3 tablespoons milk or cream, 1 teaspoon vanilla extract and a pinch of salt until smooth and pourable. Adjust milk to get a thicker or thinner drizzle.

10. Drizzle or spread the glaze over the cooled bars, let it set 15 to 30 minutes, then lift out with the parchment and cut into bars. Store in an airtight container at room temp for up to 3 days or refrigerate longer. Pro tip: they taste even better the next day once everything has melded.

Equipment Needed

1. 9×13 baking pan plus parchment paper or a good nonstick spray
2. Light colored saucepan for browning the butter
3. Large mixing bowl
4. Medium bowl for the dry ingredients
5. Measuring cups and measuring spoons
6. Whisk (for dry mix and the glaze)
7. Silicone spatula and a wooden spoon for folding and pressing the batter
8. Wire cooling rack
9. Oven mitts or potholders, and a bench scraper or offset spatula to lift bars out (optional but handy)

FAQ

Q: Can I swap old fashioned rolled oats for quick oats? A: Yes you can, but the texture will change. Quick oats make a softer, a bit mushier bar while rolled oats give chew and structure. Use the same volume, just watch baking time cause quick oats absorb faster.

Q: Do I really need to brown the butter and how cool should it be? A: Browning adds a toasty, caramel note thats worth it but you can use melted butter if youre short on time. Cool the browned butter to room temp so it wont cook the eggs; if its still warm pop it in the fridge until it firms a little but is still pourable.

Q: How do I get the glaze thicker or thinner? A: For thinner glaze add milk 1 teaspoon at a time until you like the drizzle. For thicker use less milk or add more powdered sugar. Make sure bars are fully cool before glazing or the glaze will melt and run off.

Q: Can I make these gluten free, dairy free or vegan? A: Yep. For gluten free use certified GF oats and a 1:1 gluten free flour blend. For dairy free swap in vegan butter or coconut oil and use non dairy milk in the glaze. For vegan eggs try flax eggs (1 tbsp ground flax + 3 tbsp water per egg), bars may be a touch denser.

Q: How should I store or freeze the bars? A: Store in an airtight container at room temp up to 3 days or in the fridge up to a week. To freeze wrap bars individually and store in a freezer bag up to 3 months. Thaw at room temp or microwave for 10-15 seconds to soften.

Q: My bars turned out too crumbly or too dense, what happened? A: Crumbly usually means too much dry ingredient or underbaked – measure flour and oats by spooning and leveling, press the dough firmly in the pan, and dont underbake. Too dense can be from overpacking, overmixing, or not enough leavening/liquid. Small fixes: check measurements, dont overmix, and try one extra egg or a splash more milk next batch.

Iced Oatmeal Cookie Bars Recipe Substitutions and Variations

Unsalted butter (browned): swap 1:1 with solid coconut oil for similar texture, or use vegan stick margarine 1:1; for lower fat try 1/4 to 1/2 cup applesauce plus 1/4 cup oil (bars will be softer). Tip: if using coconut oil, cool until slightly firm so dough doesn’t get greasy.
Eggs: replace each egg with 1 tbsp ground flaxseed + 3 tbsp water (mix, wait 5 min) for best binding; or use 1/4 cup mashed banana or applesauce per egg (adds sweetness and moisture); or follow package directions for a commercial egg replacer. Banana will change the flavor, just so you know.
All purpose flour: swap cup for cup with a gluten free 1:1 baking blend that contains xanthan gum, or use white whole wheat pastry flour for a nuttier, slightly denser bite; if using oat flour, replace only up to half the AP flour and expect a denser crumb, add a little extra liquid if dough seems dry.
Old fashioned rolled oats: use quick oats in the same amount for a softer, more uniform bar; or pulse half the rolled oats briefly in a food processor to make coarse oat flour for better binding and less crumble. Don’t use steel cut oats.

Pro Tips

1. Let the browned butter cool until it’s just warm not hot before you add the eggs. If it’s too hot you’ll end up with scrambled eggs in the batter. Also scrape the little browned bits into the mix they carry tons of nutty flavor.

2. For a chewier texture toast the oats in a dry skillet for 2 to 4 minutes until they smell toasty, or pulse about a cup of the oats once in a food processor so you get some finer pieces. It changes the mouthfeel big time.

3. If you use raisins or dried fruit give them a quick soak in hot water orange juice or even a splash of rum for 10 minutes then pat dry. Theyll stay plump and not suck moisture out of the bars.

4. For clean cuts and neat glaze: let the glaze sit until just set then chill the pan 15 to 30 minutes. Use a sharp knife warmed under hot water and wiped dry between each slice for perfect edges. Store layers separated with parchment so they dont stick.

Iced Oatmeal Cookie Bars Recipe

Recipe by Kate Sinclair

0.0 from 0 votes

I turned a browned butter blondie idea into iced oatmeal cookie bars that began as a kitchen experiment and became my favorite Oatmeal Cookie Bars.

Servings

servings

Calories

261

kcal

Equipment: 1. 9×13 baking pan plus parchment paper or a good nonstick spray
2. Light colored saucepan for browning the butter
3. Large mixing bowl
4. Medium bowl for the dry ingredients
5. Measuring cups and measuring spoons
6. Whisk (for dry mix and the glaze)
7. Silicone spatula and a wooden spoon for folding and pressing the batter
8. Wire cooling rack
9. Oven mitts or potholders, and a bench scraper or offset spatula to lift bars out (optional but handy)

Ingredients

1 cup (2 sticks) unsalted butter, browned and cooled
1 cup packed light brown sugar
1/2 cup granulated sugar
2 large eggs, room temp
2 teaspoons vanilla extract
1 1/2 cups all purpose flour
1 teaspoon baking soda
1/2 teaspoon fine sea salt
3 cups old fashioned rolled oats
1 teaspoon ground cinnamon
1/4 teaspoon ground nutmeg
1 cup raisins or chocolate chips, optional
1/2 cup chopped pecans or walnuts, optional
1 1/2 cups powdered sugar (for glaze)
2 to 3 tablespoons milk or cream (for glaze)
1 teaspoon vanilla extract (for glaze)
Pinch of salt (for glaze)

Directions

Preheat oven to 350°F (175°C). Line a 9×13 pan with parchment paper leaving an overhang or spray it well so bars come out easy.
Brown 1 cup (2 sticks) unsalted butter in a light colored saucepan over medium heat, swirling often until the milk solids turn golden brown and it smells nutty, about 5 to 7 minutes. Remove from heat and let cool until warm but not hot so you dont scramble the eggs.
In a large bowl mix 1 cup packed light brown sugar and 1/2 cup granulated sugar with the cooled browned butter until mostly smooth. Add 2 large room temp eggs one at a time, mixing after each, then stir in 2 teaspoons vanilla extract.
In another bowl whisk together 1 1/2 cups all purpose flour, 1 teaspoon baking soda, 1/2 teaspoon fine sea salt, 1 teaspoon ground cinnamon and 1/4 teaspoon ground nutmeg.
Add the dry mix to the wet and stir just until combined, dont overmix. Then fold in 3 cups old fashioned rolled oats and if using, fold in 1 cup raisins or chocolate chips and 1/2 cup chopped pecans or walnuts.
Scrape the batter into the prepared pan and press it into an even layer with a spatula or the back of a spoon. A slightly damp spatula helps get a smooth top without sticking.
Bake for 20 to 25 minutes until the edges are golden and the center is set but still a little soft. Rotate the pan halfway through if your oven bakes unevenly.
Cool the bars completely in the pan on a wire rack, at least 45 minutes to an hour. If you glaze while warm the icing will run off and get soggy.
Make the glaze by whisking 1 1/2 cups powdered sugar with 2 to 3 tablespoons milk or cream, 1 teaspoon vanilla extract and a pinch of salt until smooth and pourable. Adjust milk to get a thicker or thinner drizzle.
Drizzle or spread the glaze over the cooled bars, let it set 15 to 30 minutes, then lift out with the parchment and cut into bars. Store in an airtight container at room temp for up to 3 days or refrigerate longer. Pro tip: they taste even better the next day once everything has melded.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.