Lime Slime Cupcakes

halloween slime cupcakes with green frosting on it. on an orange linen

5 from 2 votes

These fun Halloween Lime Slime Cupcakes are neon green lime cupcakes filled with a lime curd colored green for the slime effect and topped with green American buttercream.

Prep Time30

Cook Time15

Chill Time1

Servings: cupcakes

Author: Miranda Couse

Ingredients

Lime Curd

3 large eggs
¾ cup granulated sugar
¼ teaspoon salt
½ cup lime juice
1 tablespoon lime zest
¾ cup unsalted butter
neon green food coloring or green and yellow food coloring

Lime Cupcakes

6 tablespoons unsalted butter room temperature
¾ cup granulated sugar
⅓ cup egg whites about 3 eggs worth
⅓ cup vanilla Greek yogurt
⅓ cup whole milk
¼ cup lime juice
1 teaspoon vanilla extract
2 teaspoons lime zest
green food coloring
1 ½ cup all-purpose flour
2 teaspoons baking powder
½ teaspoon salt

Frosting

1 cup butter room temperature
1 teaspoon vanilla extract
1 teaspoon salt
4 cups powdered sugar
3-4 tablespoons whole milk
neon green food color or green and yellow food coloring

Instructions

Lime Curd

Begin by making the lime curd since it will need to chill in the refrigerator to setup.
In a small sauce pan, add the 3 large eggs, ¾ cup granulated sugar, ¼ teaspoon salt, ½ cup lime juice, and 1 tablespoon lime zest. Whisk until combined.
Place over medium heat and let the curd come up to a bubble.
As the curd begins to bubble, start stirring constantly until the mixture thickens and coats the back of a wooden spoon.
Remove from the heat.
Strain the hot curd with a medium sized bowl with a fine mesh strainer on top of the bowl. This will catch any cooked eggs and most of the zest.
Add the ¾ cup unsalted butter and neon green food coloring to the strained curd. Whisk until the butter has melted and the mixture is smooth.
Cover with plastic wrap and gently press it down until it’s touching the top of the curd to prevent a skin from forming during the chill time.
Place in the fridge and allow to chill for about an hour to set up.
While the curd is chilling, make the cupcakes.

Cupcakes

Preheat the oven to 350 degrees F and line each cavity in your cupcake pans with paper liners. Set aside.
In a large bowl, add the 6 tablespoons unsalted butter and ¾ cup granulated sugar. Beat with a hand mixer on medium speed until creamed, about 2 minutes.
Add the ⅓ cup egg whites and continue to mix on medium speed for another 2 minutes or until light and fluffy. Scrape down the bowl.
Add the ⅓ cup vanilla Greek yogurt, ⅓ cup whole milk, ¼ cup lime juice, 1 teaspoon vanilla extract, 2 teaspoons lime zest, and green food coloring. Mix on low speed until combined. Scrape the sides of the bowl.
Add the 1 ½ cup all-purpose flour, 2 teaspoons baking powder, and ½ teaspoon salt to the wet ingredients. Beat on low speed for about a minute until most of the flour is combined and then turn the mixer up to medium and beat until thoroughly combined. Stop and scrape the sides if needed and mix in any remaining bits.
Fill each cupcake liner 2/3 full of cake batter.
Place in the preheated oven and bake for 14 to 16 minutes or until a toothpick inserted in the center of one of the cupcakes in the center of the pan comes out clean or with moist crumbs. Remove from the oven and allow to cool completely before frosting them.

Frosting

In a large bowl, add the 1 cup butter, 1 teaspoon vanilla extract, and 1 teaspoon salt. Beat using a hand mixer on medium speed until smooth.
Add about half of the 4 cups powdered sugar and half of the 3-4 tablespoons whole milk. Beat on low speed until combined. Add in the remaining powdered sugar and mix until smooth.
Turn the speed to medium/high and beat an additional minute until the frosting is light and fluffy. The frosting should be a stiff pipeable consistency. Don’t add the remaining milk unless the frosting still looks dry at this point.
Add in your neon green food color and beat until there are no white streaks left in the frosting.

To Assemble

Once the cupcakes have cooled and the curd has set up, it’s time to assemble.
Scoop the frosting into a disposable piping bag or large storage bag fitted with a large round tip or just a hole cut in the end or in the corner of the storage bag.
Place the lime curd in another disposable piping bag or large storage bag.
Using a paring knife and cut into the center of the cupcakes at an angle. Your cupcake piece should look like an upside down cone when it comes out.
Cut a small hole in the tip of the piping bag filled with the lime curd or in the corner of the storage bag.
Fill in the center of the cupcake with the lime curd without overfilling.
Gently place the piece of cupcake back on the top to cover the lime curd and give the frosting something to attach to.
Begin piping a swirl on the outside edge of the cupcake and go around the cupcake. Then begin pulling up and spiraling inwards to cover the curd and create a swirled top. Repeat with the remaining cupcakes.
Store the cupcakes in an airtight container in the refrigerator for up to 2 days.

Notes

Lime Zest/Juice: The lime zest/juice can be substituted with the same amounts of lemons or even grapefruit.

Greek Yogurt: Any flavor Greek yogurt or even full-fat sour cream will work. The sour cream will make the cupcakes slightly less sweet.

Storage: Store the cupcakes in the refrigerator for up to 7 days.

Freezing: Leave the frosting off the cupcakes, but still fill with the lime curd. Place the cupcakes in a single layer in a freezer-safe container and store in the freezer for up to 3 months.

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