Key Lime Cupcakes with Tangy Lime Curd Filling

These Key Lime Cupcakes are packed with bright, tart lime flavor in every bite. Buttery, soft, and moist, the cupcakes are filled with tangy lime curd and finished with a smooth lime cream cheese frosting. They’re perfect for celebrations and are sure to disappear fast.

Why you’ll love these Key Lime Cupcakes:

• Bold lime flavor — the batter gets lime zest mixed into the sugar, the curd is sharp and vibrant, and the frosting includes lime juice for balance.
• Fluffy and moist — a tender crumb that stays moist for days in the refrigerator and freezes well for short-term storage.
• Simple to prepare — the batter uses a reverse-creaming approach for an easy, reliable texture, and the lime curd and frosting are straightforward to make.

Ingredient Overview:

Full measurements and directions are in the recipe card below. Key notes:

• Cake flour produces a lighter crumb — spoon and level or weigh your flour for accuracy.
• Sour cream (full-fat, room temperature) adds moisture and tenderness.
• Butter — salted is used here for flavor, but unsalted is fine if preferred; bring to room temperature.
• Eggs and milk should be at room temperature for better incorporation.
• Vinegar gives a touch of lift and helps the cupcakes stay tender.
• Lime — fresh key lime juice is best for curd and frosting; bottled juice works in a pinch.

How to Make Key Lime Cupcakes:

Step 1: Make the lime curd. Combine lime-zested sugar, eggs, and juice, cook until thickened, strain, then stir in butter and vanilla. Chill while you prepare the cupcakes.

Step 2: Start the cupcakes. Rub lime zest into the granulated sugar. Whisk together cake flour, brown sugar, baking powder, and salt. Add softened butter and oil and mix until the mixture resembles coarse sand with small butter-coated pieces.

Step 3: Add the wet ingredients. Whisk sour cream, milk, warm water, and vinegar. Add a small portion to the dry mixture to moisten, then combine the remaining liquid with beaten eggs and vanilla. Add to the batter in two parts, mixing on low until just combined — do not overmix.

Step 4: Bake. Divide batter evenly among 16–17 liners, filling about two-thirds full. Bake until a toothpick comes out with moist crumbs (about 14–17 minutes). Immediately remove cupcakes from the hot pan and cool on a wire rack.

Step 5: Core and fill. Use a cupcake corer or teaspoon to remove a portion of each cupcake’s center (about one-third to one-half down) and fill with lime curd.

Step 6: Make the frosting and frost. Beat softened butter until creamy, add powdered sugar, then add vanilla, milk, a pinch of salt, cream cheese, and lime juice to taste. Pipe swirls onto completely cooled cupcakes, create a shallow well in the center of the swirl, and top with a dollop of lime curd and graham cracker crumbs or a lime slice if desired.

Serving & Storing:

Serve immediately for the best texture. Store in an airtight container in the refrigerator for 2–3 days. Bring chilled cupcakes to room temperature 15–20 minutes before serving, or enjoy them chilled for a firmer texture. Cupcakes also freeze well (with or without filling and frosting) for 1–2 months; thaw at room temperature for 1–2 hours.

FAQs

Can I scale the recipe? Yes — the recipe scales well if you double or halve it.

Special Tools:

• Piping tip — used to pipe frosting swirls.
• Piping bag — reusable or disposable, for easier frosting.
• Offset spatula — useful for finishing the frosting.
• Cupcake corer — speeds up removing centers for filling.

More of my best lime recipes:

Cheesecake

Key lime pie cheesecake

Brownies, Blondies, & Bars

Key Lime Pie Bars with Macadamia Nut Crust

Cookies

Key Lime Pie Cookies (Make-Ahead Options!)

Cake & Cupcakes

One-Bowl Key Lime Bundt Cake with Key Lime Glaze

Did you make this recipe? Leave a comment and rating!

Key Lime Cupcakes with Lime Curd

Stephanie Simmons

Bright, tangy key lime cupcakes filled with lime curd and topped with lime cream cheese frosting.

Prep: 1 hr

Cook: 21 mins

Cupcakes Cooling: 30 mins

Total: 1 hr 51 mins

Servings: 17 cupcakes

Ingredients

Lime Curd

• 1 large lime, zested
• 3/4 cup + 2 tbsp granulated sugar (184 g)
• 3/4 cup lime juice, freshly squeezed (about 6 large limes)
• 4 large eggs, room temperature
• Pinch of salt
• 1/2 tsp vanilla extract
• 6 tbsp salted butter, cubed, room temperature (85 g)

For the Cupcakes

• 4 large limes, zested
• 1 cup granulated sugar (210 g)
• 1/2 cup full-fat sour cream, room temperature (120 g)
• 1/3 cup + 1 tbsp milk, room temperature (90 g)
• 1 tbsp warm water (15 g)
• 1/2 tsp vinegar
• 1 1/2 cups + 1 tbsp cake flour, spooned & leveled or weighed (180 g)
• 3 tbsp light brown sugar, packed (36 g)
• 1 1/2 tsp baking powder
• 1/8 tsp salt
• 7 tbsp salted butter, softened (100 g)
• 2 tbsp vegetable oil (27 g)
• 1 tbsp vanilla bean paste (or extract)
• 2 large eggs, room temperature

Lime Cream Cheese Frosting

• 1/2 cup + 2 tbsp salted butter, softened (141 g)
• 3 to 3 1/3 cups powdered sugar (340–386 g), adjust to taste
• 1–2 tbsp milk to help combine (15–30 g)
• 1 tbsp vanilla bean paste or extract
• Pinch of salt
• 2 oz cream cheese, softened (57 g)
• 2–3 tbsp lime juice, to taste

For Garnish

• Graham cracker crumbs
• Lime slices

Instructions

• Lime curd filling: Make the lime curd (see ingredient list). You can also use store-bought lime curd.
• Prep: Preheat oven to 350°F. Line two cupcake pans for 16–17 cupcakes.
• Start the batter: Rub lime zest into the granulated sugar. Combine the flour, brown sugar, baking powder, and salt. Add softened butter and oil and mix on low until sandy with some butter-coated pieces remaining.
• Finish the batter: Whisk sour cream, milk, water, and vinegar. Stir 2 tbsp of this into the dry mixture to moisten. Mix vanilla and eggs into the remaining liquid, then add the liquid to the batter in two additions, mixing on low until just combined. Do not overmix.
• Bake: Divide batter among liners, filling about 2/3 full (roughly 52 g batter per cupcake). Bake 14–17 minutes or until a toothpick shows moist crumbs. Remove cupcakes from the pan and cool completely on a wire rack.
• Make the frosting: Beat butter until creamy, add powdered sugar and milk as needed, then add vanilla, salt, and cream cheese (beat cream cheese in last to prevent weeping). Adjust consistency with fridge time if too soft. Pipe swirls onto cooled cupcakes, create a shallow well in the center, and top with lime curd and graham cracker crumbs.
• Serve & store: Add extra lime curd and garnish. Store in an airtight container in the refrigerator for 2–3 days or freeze for 1–2 months. Thaw at room temperature before serving.

Notes

Vanilla bean paste: offers a stronger vanilla flavor, but vanilla extract works fine.

Some measurements are intentionally precise based on recipe testing. Using a kitchen scale will yield the most consistent results.

Nutrition

Serving: 1 cupcake — Calories: 410 kcal; Carbohydrates: 57 g; Protein: 5 g; Fat: 19 g; Saturated Fat: 11 g; Sugar: 46 g. Nutrition is approximate.