Fudgy Brownie Bars with Salted Vanilla Buttercream

Jordan Warren
Dec 12, 2024
5 min read

Nothing wrong with being a bit salty.

There's something irresistible about the combination of rich, fudgy brownies and a creamy, salted vanilla bean buttercream frosting. These brownie bars are perfect for special occasions or just a sweet treat to share. The deep chocolate flavor paired with the light, fluffy frosting creates a dessert that will disappear in minutes!

Bonus: they're customizable with sprinkles and decorations for any theme or celebration!

As always, my best tips are below just before the recipe to help you recreate these effortlessly and successfully like a pro!

Frosting Tips

For spreading: Chill the brownies briefly to firm up before spreading the frosting for a cleaner finish. Use an offset spatula for even coverage.
For piping: Add an extra tbsp of powdered sugar to stiffen the frosting slightly for piping designs. Use a star tip for swirls or dropping little stars onto the brownies as I did in this recipe. Use a round tip for sleek designs.
Sprinkle ideas: Use nonpareils, sugar pearls, or confetti sprinkles for decoration. Avoid heavier sprinkles that might collapse intricate frosting designs.

Storage tips

Room temperature: Store in an airtight container for up to 2 days.
Refrigerator: Store for up to 1 week. Bring to room temperature before serving for the best texture.
Freezer: Freeze frosted brownies for up to 2 months. Wrap individually in plastic wrap, then place in a freezer-safe container.

***I always recommend eating baked goods the day of and storing at room temperature for a few days. Freezing and refrigerating dries out the baked goods and can alter the texture of the frosting.

Weight vs. Volume

For the most fudgy bars, I always like to weight my ingredients in grams for precise measurements and accuracy. I have included both weight and volume measurements in case you do not yet have a kitchen scale. Please see this article on how to measure flour accurately to avoid cakey bars.

Tips for clean, cohesive cuts:

I often get asked when I make bars how I get such clean and precise cuts. Below are my best tips for making cuts that make your bars look nice and neat.

Chill the brownies first: Let them come to room temp in the pan, once frosted place brownies in the fridge for 15-20 mins to firm up. This makes the frosting and brownie layer more stable and easier to cut.
Use the right knife: A sharp chef's knife works best. Serrated knives can be used, but these can sometimes create jagged edges and crumbs.
Warm the knife: Run the knife under hot water or dip it into a cup of hot water, then wipe it dry before cutting. The warmth helps glide through the brownie and frosting layers without sticking.
Clean the knife between cuts: Wipe the blade with a damp cloth or paper towel after each cut to remove crumbs and frosting buildup. This ensures every slice is neat.
Mark before cutting: Lightly score the top of the frosting with a knife or toothpick to create guidelines before making the cuts for even pieces.
Use a ruler for precision: For evenly sized bars, use a ruler to measure and mark the cutting lines. For a typical 8x8 inch pan, you can cut:
1. 16 bars: 4 rows by 4 columns for smaller pieces
2. 9 bars: 3 rows by 3 columns for larger servings.
Lift out the brownies: If you've lined your pan with parchment paper, use the overhand to lift the brownie block out of the pan before cutting. (This is one reason I always recommend lining pans and dishes with parchment paper.) Place on a flat surface for even slicing.
Avoid Overbaking: Slightly underbaked brownie bars are easier to cut cleanly and stay moist. Overbaked brownies can crumble when sliced.
Frost after slicing: If you plan to pipe designs on top of your bars, slice the bars into individual squares using the tips above before piping the frosting. After piping the frosting, chill in the fridge for about 10 minutes to set the frosting before adding the sprinkles to firm up the piped designs.

Fudgy Brownie Bars with Salted Vanilla Bean Buttercream Recipe

Yield: 16 small bars or 9 large bars

Serving size: 1 bar

Prep time: 25 minutes

Cook time: 23-25 minutes

Total time: 50 minutes, plus any additional chilling time (optional)

Ingredients

For the brownies:

3/4 cup (170g) unsalted butter, melted
3/4 cup (150g) granulated sugar
3/4 cup (150g) brown sugar
1 whole + 1 yolk large egg
1 1/2 tsp (7ml) vanilla extract
3/4 cup + 1 tbsp (115g) all-purpose flour
1/2 cup (50g) unsweetened cocoa powder
1/4 tsp (1.5g) salt
1/2 cup (100g) semi-sweet chocolate chips

For the salted vanilla bean buttercream:

3/4 cup (170g) unsalted butter, softened
2 1/2 cups (300g) powdered sugar
1 1/2 tsp vanilla bean paste
1/4 tsp salt
2-3 tbsp heavy cream, if needed for consistency

Directions:

Preheat the oven to 350F. Line an 8x8 inch baking pan with parchment paper, leaving an overhang for easy removal.
In a microwave safe bowl, melt 170g (3/4 cup) of unsalted butter. Let it cool slightly.
In a large mixing bowl, whisk together 150g (3/4 cup) of granulated sugar and 150g (3/4 cup) of brown sugar. Stir in the melted butter until smooth. Whisk in 1 whole egg and 1 yolk along with 1 1/2 tsp (7ml) of vanilla extract. Mix until fully combined.
Sift together 115g (3/4 cup + 1 tbsp) of flour, 50g (1/2 cup) of cocoa powder, and 1/4 tsp (1.5g) of salt. Gradually fold the dry mixture into the wet mixture until just combined. Do not overmix.
Spread the batter evenly into the prepared pan and smooth the top. Bake for 23-25 minutes, or until the edges are set and the center appears to be slightly underbaked. A toothpick should come out with a few moist crumbs.
Allow the bars to cool completely in the pan before frosting. If spreading the frosting on top with a spatula rather than piping, chill cooled bars covered in the fridge for about 20 minutes or in the freezer for about 5-7 minutes)
Make the frosting:
1. In a large bowl, beat 3/4 cup (170g) of softened butter on medium speed until creamy and smooth, about 2-3 minutes. Using a stand mixer is ideal, but a hand mixer will work as well. If whisking by hand, whisk vigorously for best results.
2. Gradually add 2 1/2 cups (300g) of sifted powdered sugar. Beat on low speed until combined, then increase to medium speed.
3. Add 1 1/2 tsp vanilla bean paste and 1/4 tsp salt. Mix until evenly incorporated and the frosting is fluffy.
4. Add 2-3 tbsp of heavy cream, 1 tbsp at a time, until the frosting reaches a spreadable or pipeable consistency (depending on which decoration method you choose). Beat on high for 2-3 minutes for a light, fluffy texture.
Cut into 16 small squares or 9 larger squares and serve right away. If piping a design, you may want to cut your bars evenly first, then pipe your designs on to prevent cutting into your frosting.

Nutrition Information per serving: (assuming you are cutting into 16 bars)

Calories: 285

Fat: 15g

Carbs: 37g

Protein: 3g

Weight Watchers Points: (assuming you are cutting into 16 bars)

12 points per serving.

Nutrition information and WW points are always approximate and are subject to vary based on ingredients and servings used. I always recommend using your recipe builder for the most accurate macro or point count.