Soft and chewy brown butter pistachio oatmeal cookies stuffed with a thick layer of fudge – aka pistachio oatmeal fudge bars.
This post may contain affiliate links, please read the privacy policy for details. | Recipe updated 05/07/25.
pistachio oatmeal fudge bars
Pistachios and brown butter are truly just made for each other. These brown butter pistachio fudge bars start with a brown butter pistachio oatmeal cookie dough. It’s soft, chewy, crunchy (from the pistachios), super flavorful, and delicious. And of course we want to make that even more delicious, we’re stuffing the cookies with a thick layer of easy, chocolatey, rich fudge.
expert baking tips
Weigh your ingredients:
My recipes are all written in grams because it is the most accurate way to bake. When you use a kitchen scale, you ensure that your baked goods turn out as close to the written recipe as possible. Plus, the cleanup is way easier when using a scale! I will provide standard cup measurements but please note that I have not tested the recipe using cup measurements and therefore can not guarantee your recipe will come out how mine did. Here is my favorite kitchen scale.
Mix the dough carefully:
When adding in the flour, only fold the mixture just until no flour streaks remain. Over mixing the dough leads to more gluten formation, which can make the dough more tough.
A note on oven temperature:
Ovens vary and fluctuate in temperature and might not always actually be at the temperature they claim to be at. If you love to bake like I do, I highly recommend getting an oven thermometer. They are super helpful for letting you know when your oven might be lying to you! I use this one.
pistachio oatmeal fudge bar ingredients –
brown butter pistachio cookie bars:
- All purpose flour: for structure and chewiness.
- Rolled oats: I recommend rolled oats for the best texture.
- Baking soda & baking powder: helps the cookies rise and the edges crisp up.
- Salt: to help balance and bring out the sweetness of the cookies
- Unsalted butter: for tenderness and flavor. You can use salted butter in place of the unsalted, just be sure to omit the extra salt from the cookies. We’ll also be browning the butter for some extra delicious toasty flavor. If you’re looking to make this dairy-free, Miyoko’s Creamery vegan butter has the ability to brown just like regular butter and works like a charm.
- Granulated sugar & light brown sugar: a combination of both gives us cookies with crispy edges and soft and chewy centers.
- Egg yolk: for binding and for moisture.
- Milk: for moisture – use your favorite dairy or non-dairy milk here.
- Vanilla: for flavor.
- Pistachios: for flavor and texture. You can substitute in any other nut here, or omit them and replace them with chocolate chips (or nothing) if you’d like.
fudge:
- Semi-sweet chocolate chips: for the fudge layer. You can substitute in a semi sweet chocolate baking bar as well.
- Unsalted butter: for some richness. You can also use salted butter, just be sure to omit the extra salt from the fudge.
- Sweetened condensed milk: makes the fudge rich and creamy.
- Vanilla & salt: for flavor.
how to make pistachio oatmeal fudge bars
Here’s a little look into the process of making these cookie bars. The full recipe is at the end of this blog post!
- Make the brown butter, then mix in the sugars, egg, and vanilla.
- Fold in the dry ingredients, then bake 2/3 of the dough in a loaf pan.
- While the first part of the cookie dough is baking, make the fudge.
- Pour the fudge over the cookie bars and place the remaining cookie dough on top. Bake, then slice, serve, and enjoy!
pistachio oatmeal fudge bars
recipe q&a
What is brown butter?
Brown butter is super simple to make so don’t worry! It’s just regular butter that is cooked on the stove until some of the moisture evaporates, allowing the milk solids in the butter to be toasted. The result is this butter with an amber hue and little speckles that has a toasted and slightly nutty aroma.
can I double this recipe?
Definitely – you can double the recipe and bake it in two loaf pans, or in one 8″ square pan.
can I make these cookies ahead of time?
Definitely – cookie dough really only gets better with time. You can keep the cookie dough tightly covered in the fridge for up to 2 days before baking.
How to store oatmeal fudge bars
Store these cookie bars in an airtight container at room temperature. They will keep for up to 5 days, but will taste the best 1-3 days after baking.
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Pistachio Oatmeal Fudge Bars
Ingredients
Brown Butter Pistachio Cookie Dough
- 70 g unsalted butter (5 tbsp.)
- 56 g pistachios crushed (½ c.)
- 50 g light brown sugar (¼ c.)
- 25 g granulated sugar (2 tbsp.)
- 1 egg yolk room temperature
- 2 tsp. milk of choice
- 1 tsp. vanilla extract
- 70 g all purpose flour (½ c. + 1 tbsp.)
- 40 g rolled oats (⅓ c. + 1 tbsp.)
- ¼ tsp. baking soda
- ¼ tsp. baking powder
- ¼ tsp. salt
Fudge
- 110 g semi sweet chocolate chips (⅔ c.)
- 100 g sweetened condensed milk (¼ c. + 1 tbsp.)
- 14 g unsalted butter (1 tbsp.)
- ⅛ tsp. salt
Instructions
Brown Butter Pistachio Cookie Dough
- Preheat the oven to 350°F / 175°C. Butter and line an 8×4" loaf pan with parchment paper.
- Brown the butter: In a small saucepan set over medium heat, melt the butter. Stir the butter occasionally until it turns amber in color and develops little brown specks.
- Pour the brown butter into a medium sized mixing bowl and set it in the freezer for 5 minutes.
- To the brown butter, whisk in the brown sugar and granulated sugar.
- Whisk in the egg yolk, milk and vanilla until very well combined.
- Add in the flour, oats, baking soda, baking powder, and salt. Use a rubber spatula to fold the mixture together until only a few flour streaks remain. Add in the pistachios, and continue folding just until no flour streaks remain.
- Transfer ~⅔ of the cookie dough to the prepared baking pan. Use your hands or the back of a measuring cup to pat the dough down into an even layer. Bake for 12-15 minutes, until the edges start to turn golden brown.
- While the first layer is baking, make the fudge.
Fudge
- Add the chocolate, sweetened condensed milk, butter, and salt to a medium sized saucepan.
- Place the saucepan over medium heat, and stir occasionally until the mixture is completely melted and smooth. Remove from the heat.
- Once the first cookie layer is done baking, pour the fudge over the cookie layer and smooth it out into an even layer.
- Place small pieces of the remaining cookie dough randomly over the fudge layer.
- Bake for an additional 12-15 minutes or until the dough turns golden brown. Wait for the bars to cool to room temperature before slicing. Serve, and enjoy!
Notes
Nutrition
Please note that the nutrition facts are only an estimate and may vary based on different brands of ingredients and any substitutions made.
Delicious recipe, thanks for sharing. Can you please share the substitute for egg? If we don’t have pistachios in hand, any other recommendations for the same?
I can’t wait to try these and tag you.
Thanks & Regards
Thank you so much! I don’t have experience with egg replacements, but I’ve heard great things about flax eggs so I would recommend that. If you don’t have pistachios you could of course just leave them out or just use your favorite nut – any would be delicious here! 🙂
These were delicious! Everyone loved them 🙂
Thank you so much! 🙂