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Key Lime Cupcakes

Key Lime Cupcakes

These bright and refreshing Key Lime Cupcakes feature tender, moist cupcakes infused with fresh key lime juice and zest, topped with creamy homemade lime buttercream. Finished with fresh lime zest or a small lime wedge, they offer the perfect balance of sweet, tangy, buttery, and citrusy flavors.
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Prep Time 25 minutes
Cook Time 22 minutes
Total Time 47 minutes
Servings: 12 Cupcakes
Course: Dessert
Cuisine: American
Calories: 360
Ingredients Equipment Method Notes

Ingredients
  

For the Key Lime Cupcakes
  • 1½ cups all-purpose flour
  • 1½ teaspoons baking powder
  • ¼ teaspoon baking soda
  • ¼ teaspoon salt
  • ½ cup unsalted butter softened
  • ¾ cup granulated sugar
  • 2 large eggs preferably room temperature
  • 1 tablespoon finely grated key lime zest
  • 1 teaspoon vanilla extract
  • ½ cup milk or buttermilk
  • 2 tablespoons fresh key lime juice
For the Lime Buttercream
  • ½ cup unsalted butter softened
  • 2 cups powdered sugar
  • 1½ –2 tablespoons fresh key lime juice
  • 1 teaspoon finely grated key lime zest
  • 1 teaspoon vanilla extract
  • Pinch of salt
  • 1 –2 teaspoons milk if needed for consistency
For Garnishing
  • Fresh key lime zest
  • Thin key lime slices or small wedges optional

Equipment

  • 12-cup muffin or cupcake pan
  • 12 Paper cupcake liners
  • Large mixing bowl
  • Medium mixing bowl
  • Electric hand mixer or stand mixer
  • Whisk
  • Rubber spatula
  • Measuring cups and spoons
  • Fine citrus zester
  • Citrus juicer
  • Cookie scoop or spoon
  • Wire cooling rack
  • Piping bag and star piping tip, optional

Method
 

Prepare the Oven
  1. Preheat the oven to 350°F (175°C). Line a 12-cup muffin pan with cupcake liners and set aside.
Combine the Dry Ingredients
  1. In a medium bowl, whisk together the flour, baking powder, baking soda, and salt until evenly distributed. Set aside.
Cream the Butter and Sugar
  1. In a large bowl, beat the softened butter and granulated sugar until light, fluffy, and noticeably paler in color, about 2–3 minutes.
Add the Eggs
  1. Add the eggs one at a time, beating well after each addition. Scrape down the sides of the bowl as needed.
Add the Lime and Vanilla
  1. Mix in the fresh key lime zest and vanilla extract until evenly incorporated.
Combine the Batter
  1. Add the dry ingredients in portions, alternating with the milk or buttermilk. Mix gently after each addition and stop mixing as soon as the flour is incorporated.
  2. Add the fresh key lime juice and mix just until combined. Do not overmix.
Fill the Cupcake Pan
  1. Divide the batter evenly among the prepared cupcake liners, filling each about two-thirds full.
Bake
  1. Bake for 18–22 minutes, or until the cupcakes are lightly golden and a toothpick inserted into the center comes out clean or with a few moist crumbs.
Cool
  1. Allow the cupcakes to cool in the pan for several minutes, then transfer them to a wire rack. Cool completely before frosting.
Prepare the Lime Buttercream
  1. Beat the softened butter until smooth and creamy. Gradually add the powdered sugar, mixing on low speed until incorporated.
  2. Add the key lime juice, lime zest, vanilla extract, and salt. Beat on medium-high speed until the frosting is light and fluffy.
  3. If the frosting is too thick, add milk a teaspoon at a time. If it is too soft, add a little more powdered sugar.
Frost and Garnish
  1. Pipe or spread the lime buttercream over the completely cooled cupcakes. Finish with fresh lime zest or a small key lime wedge.
  2. Serve and enjoy!

Notes

Fresh limes are recommended: Fresh key lime juice and zest provide the brightest flavor. Regular Persian limes can be substituted if key limes are unavailable.
Zest before juicing: Whole limes are much easier to zest than squeezed ones.
Avoid the white pith: Only grate the green outer skin because the white pith can taste bitter.
Do not overmix: Mix the batter only until the ingredients are combined to keep the cupcakes soft and tender.
Cool completely before frosting: Warm cupcakes can melt the buttercream and make it difficult to achieve attractive frosting swirls.
For stronger lime flavor: Increase the amount of fresh lime zest rather than adding excessive lime juice.
Storage: Keep frosted cupcakes in an airtight container in the refrigerator for up to 3–4 days. Allow them to sit at room temperature briefly before serving for the best texture.
Make-ahead: The cupcakes can be baked a day ahead, while the frosting can be prepared several days ahead and refrigerated until needed.
Freezing: Unfrosted cupcakes can be frozen in an airtight freezer-safe container for approximately 2–3 months for best quality.
Diet note: The standard recipe is vegetarian but is not gluten-free, vegan, keto, or low-carb.