Key Lime Brownie Bars by ~ Fudgy, bursting with Key Lime flavor and irresistible! The texture of these citrus bars is very similar to brownies and tasting the glaze gives one the sense of being in the tropics. Perfect for summer entertaining and picnics! Includes gluten free option. #easy #bar #dessert #recipe

Key Lime Brownie Bars or Key Lime Brownies

  • Prep Time: 30 minutes
  • Cook Time: 25 minutes
  • Total Time: 55 minutes
  • Yield: Makes 9 to 12 bars or 16 small bars.


Fudgy, bursting with Key Lime flavor and irresistible! The texture of these Key Lime Brownie Bars is very similar to brownies and tasting the glaze gives one the sense of being in the tropics. Perfect for summer entertaining and picnics. Recipe includes an equally irresistible gluten free version.


  • For the Key Lime Brownie Batter
  • 1 cup (125 grams) all-purpose flour, such as Gold Medal®
  • 1 cup (200 grams) organic granulated cane sugar
  • ½ teaspoon (2.4 grams) kosher salt
  • 2/3 cup (150 grams) unsalted butter, softened to room temperature
  • 2 large eggs + 1 large egg white (mine weighed 137 grams w/o shells)
  • 1 tablespoon + ½ teaspoon (7 grams) freshly grated Key Lime zest
  • 2 tablespoons + 2 teaspoons (40 ml) freshly squeezed Key Lime juice
  • For the Key Lime Glaze
  • ¾ cup (94 grams) confectioners’ sugar, sifted
  • 1 tablespoon + 1 teaspoon (20 ml) freshly squeezed Key Lime juice
  • 2½ teaspoons (5 grams) freshly grated Key Lime zest
  • Special Equipment & Supplies
  • Parchment paper for lining baking pan, such as Beyond Gourmet™


  1. Arrange oven rack in lower third of oven and preheat oven to 350ºF. Lightly grease a 9×9-inch metal baking pan with shortening. (I like to use my Williams-Sonoma Goldtouch® Nonstick Square Cake Pan.) Line pan with baking parchment so there is an overhang. Do this by measuring parchment 4 inches in length additionally at each side of pan. This will allow 2 inches of coverage on each end once folded and tucked in. This will create “handles” which will help removing bars from pan and to transfer to cutting board to cut into even bars after cooling.
  2. Prepare the Key Lime Brownie Batter: Using an electric stand mixer fitted with paddle attachment, or handheld mixer and large bowl, stir together flour, sugar and salt until well combined. Add the butter and mix until well combined, but do not “beat” at high speed which would incorporate too much air.
  3. In a small bowl, whisk the eggs, lime zest and juice together. Scrape and pour into batter using a rubber spatula. Mix together on low mixer setting until well blended and smooth, scraping down sides of bowl as necessary with rubber spatula. Or, stir by hand using a rubber spatula until well blended and smooth. Do not “beat” at high speed with mixer.
  4. With a rubber spatula, scrape batter into prepared pan and smooth the top. Bake in preheated oven until golden brown around the edges and firm to the touch in the center, about 25 minutes. (Do not bake over 25 minutes or the brownie bars will be too dry.) Transfer to wire rack and allow the brownie cake to cool at least 1 hour before removing from pan. Cool completely before spreading on glaze.
  5. Use the baking parchment on sides of pan to lift brownie cake out and transfer to cutting board. Once the brownie cake is completely cool, prepare the glaze.
  6. Prepare the Key Lime Glaze: In a medium bowl, whisk together sugar, lime juice and zest until smooth and creamy. Pour glaze over cooled brownie cake and spread evenly over the top using a metal angled icing spatula or regular icing spatula.
  7. Allow glaze to dry slightly on the surface before cutting into bars and serving. Store in airtight container at room temperature or in the refrigerator.

Recipe Notes


For Gluten Free Option: Substitute 1 cup (128 grams) Cup4Cup (C4C) Gluten-Free Flour, available at Williams-Sonoma, for regular all-purpose wheat flour called for in recipe.

Be sure to bring butter fully to room temperature. It is imperative to have your butter softened to room temperature as outlined in the next tip.

Mix the ingredients in the order stated in the recipe. The fat in the softened butter coats the flour and sugar then becoming well saturated thus creating a very moist and exceptional crumb. Do not cream the butter and sugar together, then add the eggs and flour mixture. This will create a “too cakey” texture and drier crumb. Remember, we are after dense and fudgy here.

After blending together the dry ingredients, do not “beat” in the butter, eggs, lime juice and zest and then continue beating for 2 minutes or more. This is a serious “no-no” and will just cause the batter to become aerated (incorporating air). This will then cause too many air pockets after baking as well as create an undesirable drier crumb. It is essential to “stir” in, by hand (or using the ‘stir’ setting of a stand mixer), the wet ingredients and not aerate the batter. This is how the fudgiest of brownies are mixed, by hand. Again, fudgy is what we are after.

Do not overbake. Just as with chocolate brownies, overbaking will create a dry brownie. Bake for exactly 25 minutes and no longer. Be sure that your oven is properly calibrated or use an oven thermometer to ensure the proper temperature.

After measuring confectioners’ sugar for glaze, sift to prevent lumps.

If making the glaze in advance, keep it covered with plastic food wrap to keep it smooth and prevent it from drying out.

Recipe Adapted From: Best Ever Lemon Brownie Bars by Wicked Good Kitchen™
Original Recipe Source: