Key Lime Cupcakes

These key lime cupcakes are filled with homemade key lime curd and topped with tangy cream cheese frosting and graham cracker crumbs. They taste just like classic key lime pie but in cupcake form! They're the perfect summer treat!

Course Dessert

Cuisine American

Prep Time 1

Cook Time 20

Total Time 1 20

Servings cupcakes

Calories 526kcal

Author Kyleigh Sage

Equipment

Ingredients

Key Lime Curd

½ cup granulated sugar
1 teaspoon key lime zest
3 large egg yolks
½ cup key lime juice
¼ teaspoon kosher salt
¼ cup unsalted butter

Cupcakes

½ cup unsalted butter melted
1 cup granulated sugar
1 tablespoon key lime zest
2 large eggs room temperature
2 tablespoons key lime juice
1 ½ cups cake flour substitute all purpose flour
1 ½ teaspoons baking powder
½ teaspoon kosher salt
½ cup sour cream substitute plain full-fat yogurt

Cream Cheese Frosting

1 cup unsalted butter room temperature
4 ounces cream cheese room temperature
3 ½ cups powdered sugar
2 tablespoons key lime juice

Garnish

graham cracker crumbs
key lime slices
key lime zest

US Customary - Metric

Instructions

Key Lime Curd

I recommend making the key lime curd the night before you make the cupcakes so that it has time to fully cool/set.
Create a double boiler by bringing 1-2 inches of water to a simmer in a small saucepan. Place a heatproof glass bowl on top and make sure it's not touching the water.
Add the egg yolks, sugar, key lime juice, key lime zest, and salt into the top of your double boiler.
Whisk until completely combined and then continue to whisk as the key lime curd cooks (constant whisking prevents the curd from curdling). Continue to whisk the key lime curd for 10-15 minutes or until it becomes thick and paler in color (it should be similar to the consistency of hollandaise sauce). If the lime curd isn’t thickening, turn up the heat and constantly whisk. *If your lime curd still is not thickening with the double boiler, you can transfer to a pot to cook over direct heat for a couple minutes until it fully thickens.
Once thickened, remove the glass bowl from the heat. Cut the butter into chunks and whisk into the key lime curd until fully combined and smooth.
If desired, pass through fine mesh strainer and then pour into a glass jar.
Let cool to room temperature and then cover and store in the fridge for up to a week. You'll almost certainly have some leftover key lime curd, so you can serve it with homemade crepes or scones!

Cupcakes

Preheat the oven to 350°F and line a 12 cup pan with cupcake liners.
In a medium bowl, add the sugar and key lime zest. Then use your fingers to gently massage the key lime zest into the sugar (this is optional, but helps infuse the sugar with even more key lime flavor).
Whisk the cake flour, baking powder, and salt together in a large bowl.
In a separate bowl, whisk the melted butter and flavored sugar.
Add in the eggs and key lime juice and whisk until fully combined.
Stir in about half of the flour mixture. Then stir in the sour cream and the rest of the flour mixture and mix until fully combined.
Pour about ¼ cup of batter into each cupcake liner (they should be about halfway full).
Bake at 350°F for 18-22 minutes or until a cake tester comes out clean.
Remove from pan and let cool on wire rack. Let cupcakes cool completely before filling and frosting.
Use a cupcake corer to remove the center of each cupcake, then fill with 1-2 teaspoons of cooled key lime curd.

Cream Cheese Frosting

While the cupcakes are cooling, make the frosting.
In a stand mixer fitted with the paddle attachment, cream together the softened butter and cream cheese until completely smooth.
Then add in the powdered sugar and beat on slow until combined.
Slowly add in the key lime juice until fully combined. Then beat the buttercream for 3-4 minutes on high speed until light and fluffy.
Frost cooled key lime cupcakes, then garnish with graham cracker crumbs, key lime slices, and key lime zest if desired!

Notes

These cupcakes will last in the fridge for up to 3 days. However, they taste best when served at room temperature! I like to let them sit at room temperature for about an hour before serving. But I recommend waiting to top with key lime slices until immediately before serving!

Nutrition