Recipes, Slices/Pies/Tarts

Buttermilk Brownies with Buttermilk Chocolate Frosting

These are quite possibly my new favourite brownies. Fudgey and rich, dotted with white chocolate and slathered with a generous coating of chocolate frosting, these triple chocolate brownies are decadent with just the right amount of tang from the inclusion of buttermilk.

Buttermilk Brownies with Buttermilk Chocolate Frosting

I don’t ever really need an excuse to make more brownies, but when I had some leftover buttermilk in the fridge, I was wondering if I could incorporate it into a new recipe. My go-to recipe for leftover buttermilk is normally my Red Velvet Cupcakes which keeps them light, tender and moist. Another favourite way to use up buttermilk is for pancakes. But I had a chocolate hankering, so I decided to experiment.


I honestly think my favourite part of this recipe is the buttermilk chocolate frosting. It’s so easy to make and tastes irresistible – I ate far too much of it straight out of the bowl! It spreads on thick and glossy and sets up perfectly in the fridge. I experimented with the cocoa powder to icing sugar ratio to ensure the frosting was rich and chocolatey and not *too* sweet.


I used the buttermilk in both the brownie batter AND decided to top the brownies with a rich and decadent buttermilk chocolate frosting as well. Since there wasn’t already enough chocolate going on in these brownies, I added in a cup of white chocolate chips to the batter as well.


Buttermilk Brownies with Buttermilk Chocolate Frosting

4.75 from 4 votes
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Prep Time: 25 minutes
Cook Time: 20 minutes
Total Time: 45 minutes
Servings: 16
Author: Swah


Buttermilk Brownies

  • 120 g butter
  • 1/3 cup unsweetened cocoa powder
  • 1/2 cup vegetable oil
  • 1 cup caster sugar
  • 1/2 cup brown sugar
  • 2 eggs
  • 1/4 cup buttermilk
  • 1/2 tsp vanilla extract
  • 2 cup plain flour
  • 1 tsp baking soda
  • 1/2 tsp salt
  • 1 cup white chocolate chips

Buttermilk Chocolate Frosting

  • 120 g butter
  • 1/2 cup buttermilk
  • 1/2 cup dark chocolate unsweetened cocoa powder
  • 3 cups icing sugar


  • Preheat oven to 200°C. Line a 20 cm pan with baking paper.
  • In a medium saucepan, combine the butter, cocoa powder and vegetable oil over medium-high heat until it just comes to the boil. Remove from the heat and set aside to cool down slightly.
  • Next, combine the sugars, eggs, buttermilk and vanilla in a large mixing bow
  • Slowly whisk in the melted butter mixture.
  • Add in flour, baking soda and salt, and stir just until combined. Fold in the white chocolate chips.
  • Pour into lined tin and bake for 20 minutes. Set aside to cool down.

Buttermilk Chocolate Frosting

  • Meanwhile for the frosting, add the butter, cocoa powder and buttermilk to a saucepan over medium-high heat and stir until combined.
  • Transfer melted mixture to a mixing bowl and whisk in icing sugar gradually until the frosting is smooth and thick.
  • Pour the frosting over the brownies (they don't have to be completely cooled yet) and smooth with an offset spatula.
  • Put the frosted brownies in the fridge for a few hours until set, then cut into 16 squares and enjoy!


Don’t have any buttermilk? Fear not, you can still make these brownies! Simply use the same amount of regular milk, and add 1/4 teaspoon of lemon juice to your milk in the batter, and 1/2 teaspoon of lemon juice to your milk before you add it in to the frosting. This helps recreate the tang buttermilk is known for.


I hope you enjoyed this delicious way to use up buttermilk in both brownies and chocolate frosting to produce these decadent triple chocolate brownies. And I have to warn you – you won’t be able to stop at just one!


Have you used buttermilk in baking before? What’s your favourite recipe to use it in?


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