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+ servings

Key Lime Cupcakes

These Key Lime Cupcakes are a vanilla lime cupcake base topped with lime buttercream- the ultimate combination of sweet and tart. It's basically summer in a cupcake!
Course Dessert
Cuisine American
Prep Time 30 minutes
Cook Time 18 minutes
Total Time 50 minutes
Servings 16 cupcakes
Calories 391kcal
Cost $7



  • cup all-purpose flour spooned and leveled
  • tsp baking powder
  • ¼ tsp salt
  • 1 cup granulated sugar
  • 1 stick unsalted butter room temperature
  • 1 large egg + 1 egg yolk
  • 1 tsp vanilla extract
  • ½ cup whole milk room temperature
  • 1 tbsp lime zest
  • 2 tbsp key lime juice

Key Lime Buttercream

  • 2 sticks unsalted butter room temperature
  • cups powdered sugar
  • tbsp key lime juice
  • 2 tbsp heavy cream
  • 2 tsp lime zest
  • pinch of salt


Make the Cupcakes:

  • Preheat your oven to 350° F. Prepare your muffin tin with cupcake liners.
  • In a medium bowl, combine the flour, baking powder, and salt. Set aside.
  • In a large bowl, beat the sugar and butter together until light and fluffy. Add in the egg + egg yolk and vanilla extract and mix until combined.
  • Alternate between adding the dry ingredients and the milk to the butter mixture until everything is combined. Lastly, add in the lime juice and zest, and mix until combined.
  • Divide the batter evenly between the prepared muffin tins, filling each about ⅔ full.
  • Bake until a tester inserted in the middle of the cupcakes comes back with just a few crumbs, about 15 to 18 minutes. Cool in the pans for 5 minutes before removing to a cooling rack to cool completely.

Make the Buttercream:

  • With a handheld or stand mixer fitted with a paddle or whisk attachment, beat the butter on medium speed until creamy – about 2 minutes.
  • Add the powdered sugar, lime juice, heavy cream, lime zest, and salt. Turn your electric mixture on low until the sugar has combined together, then beat on high speed for 3 minutes until light and fluffy. Scrape down the sides of the bowl when necessary.
  • If your icing seems too thick, add a tbsp of cream at a time until you reach the right consistency. If the icing is too thin, add a tbsp of powdered sugar at a time.
  • Frost the cupcakes when they are completely cooled by using an offset spatula or piping bag (or ziploc bag) and a tip. Garnish with lime zest.


  • Use room temperature butter- I like to take my butter out of the fridge about an hour before I start baking.
  • Make sure to measure your flour correctly- spoon and level is my favorite method. Use a spoon to fluff up the flour, then gently scoop it into your measuring cup without packing it. Then use the back of a butter knife to level it off.
  • Store leftovers in the fridge in an airtight container for 4-5 days. You can make cupcakes and buttercream in advance and store them in the fridge until ready to frost. Cupcakes will stay fresh in the freezer for up to 3 months. 


Calories: 391kcal | Carbohydrates: 56g | Protein: 2g | Fat: 18g | Saturated Fat: 12g | Trans Fat: 1g | Cholesterol: 59mg | Sodium: 81mg | Potassium: 40mg | Fiber: 1g | Sugar: 46g | Vitamin A: 586IU | Vitamin C: 1mg | Calcium: 38mg | Iron: 1mg