Chocolate Buttermilk-Frosted Brownies

September 10, 2015

Test Kitchen-Approved

Author Notes: Decadent and intensely fudgy, this brownie uses a riff on the simple one-bowl Baker's chocolate brownie recipe for the base. I topped it with a tangy, sweet chocolate buttermilk frosting. They are better when chilled slightly—but it's hard to wait that long to take a bite!Posie (Harwood) Brien

Makes: one 9- by 13-inch pan
Prep time: 25 min
Cook time: 40 min

Ingredients

For the brownies:

  • 4 ounces unsweetened chocolate
  • 3/4 cup butter
  • 2 cups sugar
  • 3 eggs
  • 1 teaspoon vanilla extract
  • 1 cup flour

For the frosting:

  • 1/4 cup butter
  • 3 tablespoons buttermilk
  • 3 tablespoons unsweetened cocoa powder
  • 1/2 teaspoon vanilla extract
  • 3 cups confectioners' sugar
In This Recipe

Directions

  1. Preheat the oven to 350° F. Line a 9- by 13-inch baking pan with foil and grease with butter or baking spray.
  2. In a large glass bowl, microwave the chocolate and the butter on high, checking and stirring after each 30-second interval, until the butter melts (about 2 minutes). Stir until the chocolate is fully melted.
  3. Add the sugar and mix well. Add in the eggs and vanilla and stir until combined. Add the flour and mix until well-incorporated.
  4. Pour the batter into the prepared pan and bake for about 30 minutes. The top should be crackly and a tester inserted into the middle should come out clean. Do not overbake! Remove from the oven and let cool in the pan.
  5. To make the frosting, add the butter, buttermilk, and cocoa powder to a small saucepan. Bring to a boil, whisking until smooth, and then remove from the heat. Transfer to a stand mixer (or large bowl) and add in the confectioners' sugar and the vanilla. Beat the mixture until fluffy and thick. **You might need less or more sugar, depending. Start with 2 cups, and add more if the frosting looks too thin. Also, if it isn't getting fluffy, try refrigerating the frosting for 20 minutes, and then beating it again.**
  6. Spread the frosting over the brownies. Let the frosting set (it is helpful to chill them for a little while in the refrigerator), and then slice and serve.

More Great Recipes:
Brownie|American|Buttermilk|Chocolate|Serves a Crowd|Bake|Make Ahead|Snack|Dessert

Reviews (42) Questions (0)

42 Reviews

Jon May 27, 2018
These were OK, really no different than any other brownies I’ve made from scratch.
 
Stephanie S. December 12, 2017
My frosting was grainy! What did I do wrong? Should I have sifted the confectioner’s sugar or maybe I added too much?
 
Laura N. May 5, 2017
I made this recipe gluten-free as well (I have Celiac so there's no other option for me!): Instead of all-purpose flour, I did 1/2 cup cocoa powder, 1/2 cup gluten free flour mix. I added an additional egg and 1/2 tsp. baking powder, and they look perfect! We'll see what my kids think tonight!
 
EmilyC February 6, 2017
This frosting is SO good!! I made a malted version of it yesterday by decreasing the cocoa just a bit, and adding chocolate malt powder (Ovaltine) to the frosting, to taste. The texture is just perfect for brownies.
 
Charlotte S. August 20, 2016
Followed the recipe exactly - way too sweet for me. Consistency is nice - fudgy, no baking powder/soda which is traditional. Frosting is tasty, used imported coco powder. Maybe some tart cherries would balance. Sending to the fire station with my husband....
 
Mary B. May 12, 2017
I agree! Way too sweet. I was thinking that as I added the two CUPS of sugar.
 
Melissafitz August 12, 2016
So good! My only edit was to add a couple teaspoons of espresso powder to the batter. Excellent frosting -- May become my go-to chocolate fudgey frosting!
 
ML July 22, 2016
If the frosting is finicky do you think cooling it before you begin to whip it with the confectionery sugar? At first I was thinking you could replace the buttermilk with yogurt, I do not usually have buttermilk in the house until I read the instructions that have you boil the buttermilk with the butter & cocoa. I wonder if this curdling might be the finicky problem? Years ago I had a recipe for frosting that had you make a white roux with milk & flour. Barely cooking it so it did not brown. Then you refrigerated that until cool when ready to make the icing you put in your butter and vanilla with this cooled roux whipped it up and then added the icing sugar. It was a little less sweet but it did not have a smooth texture my family loved it, I should find that recipe in my old recipe box. Now that I know a bit more about cooking and what the chemistry of it could be maybe I can figure out why it was not smooth. Ah well I should stop musing and just bake these brownies. LOL
 
Archana P. June 14, 2016
I just made it and I love the texture very much. It's not very fudge like but not cake like either. I felt like it could do with a little more chocolate to make it rich. My kids love it. I haven't made the frosting but I think we can finish the brownie very easily. Love it a lot. :-)
 
Kristin W. May 16, 2016
I needed to make this gluten free and I tend to like rich instead of dark so I took the basic recipe and adjusted it quite a lot. 8oz of chocolate (99% and 70% Scharfenberger - it's what I had), 1 cup sugar, and for the flour I used a 1:1 flour substitute + almond flour + plus cocoa powder until I had 140gms. Came out great! I'm used to cooking GF so I knew the added liquid from the chocolate would be perfect for the GF flours that tend to soak up more liquid.
 
Kristin W. May 16, 2016
*rich instead of sweet
 
Alina November 17, 2015
I would love to try this recipe. I personally love to bake anything chocolate ( my family loves chocolate, who doesn't right?) But I was also wondering if maybe this recipe will be good with vanilla ice cream? Or will the ice cream ruin the topping of the brownie. I know some desserts are just better by themselves. But I would love to make these brownies just by themselves as well. Thanks!
 
Teri September 18, 2016
What? How would ice cream ruin the frosting? Just eat it! lol
 
Liz A. October 14, 2015
microwaves - boooo
 
Cem S. March 18, 2016
You can use a double boiler instead.
 
Ila September 28, 2015
Is it confectioner's sugar or granulated?
 
Author Comment
Posie (. September 28, 2015
The sugar in the brownies is granulated, and the sugar used in the frosting is confectioner's. Enjoy!
 
Amy September 27, 2015
Consistency was far from brownie...more like semi-set cookie dough, but not cakey at all. Nor is this a fudgy recipe. Very milk-chocolate like. To me, fudgy means decadent and deep chocolate flavor. It was more the consistency of fudge rather than fudgy flavor. Icing was strange. Will stick with buttercream next time. Agreed with another user that it was very "grainy".
 
Lucy G. September 26, 2015
I live in the UK and we don't use cups as measurements. Do you know what ounces or grams I should use? Thanks!
 
Lucy S. September 27, 2015
I am a Canadian who lives in the UK every winter. Go ahead and use an average-sized tea mug as a measure. It should hold about 8 ounces, which is what a North American cup measure is.
 
Lucy G. September 27, 2015
Thank you so much!
 
Ruth S. September 25, 2015
What the time could be if I try with a glass pan?
 
Author Comment
Posie (. September 28, 2015
The time should be the same! I've made the recipe in both a glass and metal pan with good results.
 
Dhwani September 25, 2015
Can we replace the eggs with something else ? I am a vegetarian, but want to try the recipe out.
 
Author Comment
Posie (. September 28, 2015
Hm, I haven't tried this myself but I imagine you could try a flax egg replacement (1 tablespoon flaxseed meal + 2.5 tablespoons water equals one egg). I'm not sure how it will work in this recipe though -- let me know if you try it!
 
Lindsay September 23, 2015
I made this recipe today and the brownies and frosting turned out great. I stuck the frosting into the fridge like recommended to get the consistency I wanted and that helped it become thick. The top of the brownies came out crispy while the middle was very fudgy!
 
Eileen B. September 20, 2015
A dusting of icing sugar makes a nice finish, too.
 
dinah September 18, 2015
Made this tonight. Came out great! I baked it in a 8x8. Took about 50 mins. Loaded it with chocolate chips. Sprinkled with maldon salt.
 
Laura September 18, 2015
I tried making these and they came out so sugary. I could see the sugar grain on the top of the brownie....did have a fudge consistency at all!?
 
Author Comment
Posie (. September 18, 2015
Oh no, I'm sorry to hear that! They are certainly sweet, but shouldn't be overly sugary (no more so than other brownies). The only thing I can think of: Are you sure you used unsweetened baking chocolate? Or was it the frosting that was too sugary?
 
Laura September 18, 2015
That may be the problem! I used semi-sweet, it was all I had!
 
Laura September 18, 2015
Thanks!
 
Author Comment
Posie (. September 18, 2015
Sure! Glad we figured it out :) That would definitely be the culprit for sure!
 
Laura September 18, 2015
Didn't realize it could have the much of an impact!