How to Make Glow in the Dark Cupcakes

Co-authored by Quynh La and Amy Bobinger

Last Updated: December 16, 2022

If you're looking for an eye-catching treat to wow your guests, try making these cupcakes that glow under UV light! Since it's just the frosting that glows, you can use any cupcake recipe you like. You can even buy cupcakes already made from the bakery, if you like! Then, ice the cupcakes with a frosting made with tonic water, freeze the frosted cupcakes, and finish by dipping them in a mixture of gelatin and tonic water. This easy treat is sure to be a big hit!

Ingredients

Baking and Frosting Your Cupcakes

12 cupcakes
3 1/2 cups (435 g) confectioners sugar
1/2 cup (100 g) vegetable shortening
¹⁄₂ tsp (2.5 mL) vanilla extract
2 ¹⁄₂ US tbsp (37 mL) tonic water
Green food coloring (optional)

Mixing the Gelatin

1 3-oz (85 g) package lime gelatin
1 cup (240 mL) boiling water
1 cup (240 mL) chilled tonic water

Makes 12 cupcakes

Part 1

Part 1 of 4:

Making the Glowing Buttercream

1
Bake up a batch of a dozen cupcakes and let them cool. Since it's the frosting that glows, and not the cupcakes themselves, you can make any cupcakes you like. Mix up your favorite cake or cupcake recipe, then spoon the batter into 12 cups lined with paper and bake them according to the recipe. Remove the cupcakes and let them cool.^{[1]
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- If you're not familiar with making cupcakes, a simple vanilla cupcake is a great place to start.
- You can even make cupcakes from cake mix or buy pre-baked cupcakes from the bakery section if baking from scratch isn't your thing!
- Avoid cupcakes with fillings, as these may not be sturdy enough to stay intact through the dipping process.
Tip: Try experimenting with different combinations of cupcake and gelatin flavors, like key lime or strawberry cupcakes with the lime gelatin in this recipe, or lemon cupcakes with a pineapple gelatin!
2
Add all of the ingredients to a large bowl, reserving half the tonic water. Sift and measure 3 1/2 cups (435 g) of confectioner's sugar into a large bowl, then add in 1/2 cup (100 g) of vegetable shortening, ¹⁄₂ tsp (2.5 mL) of vanilla extract, and 1 ¹⁄₄ US tbsp (18 mL) of tonic water.^{[2]
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- Diet tonic water will also work for making glow-in-the-dark cupcakes, if that's what you have on hand.
- You can use pre-made buttercream, but the addition of the tonic water in this frosting will make your cupcakes glow brighter!
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3
Beat the ingredients on low speed for about 5 minutes. If you have a stand mixer or a hand mixer, turn it to low speed and beat the ingredients together. You want the sugar to be fully incorporated with the other ingredients, which takes about 5 minutes. Your buttercream should be fluffy and smooth, with a somewhat stiff consistency.^{[3]
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- If you're using a hand whisk, it will probably take closer to 10 minutes for the frosting to reach the right consistency.
4
Add the remaining 1 ¹⁄₄ US tbsp (18 mL) of tonic water and mix it in. When your buttercream is finished mixing, measure out the rest of the tonic water and pour it into the bowl with your buttercream. Then, turn the mixer back on and continue beating the frosting until the tonic water is fully incorporated.^{[4]
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- Reserving some of the tonic water at first will help you get a stiffer consistency for your buttercream. Adding it back in will help smooth it out, so it stays stiff but is still creamy enough to pipe onto the cupcakes.
5
Add a few drops of green food coloring if you want. You can leave your buttercream frosting white if you like, or you can add a little green food coloring if you'd prefer for it to be tinted. Since you're using lime gelatin, opt for 2-3 of green food coloring if you want it to be colorful.^{[5]
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- White icing glows the best. The darker you make the icing, the less it will glow.
- If you're using another flavor of gelatin, pick a color that matches! For example, you could use red food coloring for strawberry gelatin, or yellow if you're using lemon or pineapple.

Part 2

Part 2 of 4:

Icing and Freezing the Cupcakes

1
Transfer the buttercream to a piping bag. Use a spoon or a spatula to scoop up the icing and place it into a piping bag. Then, gently squeeze the top of the bag closed to push all of the frosting down into the corner. This will help remove any air bubbles that could interfere with your cupcake decorating!^{[6]
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- If you don't have a piping bag, you can put the buttercream into a large resealable plastic bag. Then, use scissors to snip off just a little of the bottom corner.
2
Pipe the icing onto the cupcakes. Hold the tip of the piping bag and gently squeeze so some of the icing comes out. Squeeze from the top of the bag, gradually working down as you use the frosting. Try to pipe a peak onto the top of each cupcake.^{[7]
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- Start with just a little icing on each cupcake to ensure you have enough to frost each one, then go back and add more. Try to divide the frosting evenly across all 12 cupcakes. This should be about 2 tbsp (32 g).
- If the icing slides off the cakes, don’t fret. Simply pop the piping bag in the fridge for a few minutes to help the icing stiffen.
- If you have different tips for your piping bag, a star tip really emphasizes the glowing effect!^{[8]
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3
Put the cupcakes in the freezer for at least 1 hour. In order to ensure the cupcakes are sturdy enough to dip in your glow-in-the-dark concoction, they need to be chilled. Leave the cupcakes in the freezer for at least an hour, or you can leave them in overnight if you want.^{[9]
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- When the cupcakes are ready, the frosting should be hard to the touch.

Part 3

Part 3 of 4:

Mixing the Gelatin

1
Bring 1 cup (240 mL) of water to a boil in a small saucepan. It should only take 3-5 minutes for your water to come to a boil. Once it's boiling steadily, remove the saucepan from the heat. Use caution when you're boiling water so you don't burn yourself!^{[10]
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- Your saucepan should be big enough to hold 2 cups (470 mL) of liquid, but it shouldn't be too big, or the gelatin mixture won't be deep enough to completely coat the icing. A 1–1 ¹⁄₂ qt (950–1,420 mL) saucepan is a good option for this.
- If you don't have a small saucepan, boil the water in a larger saucepan, then pour it into a heat-safe bowl after you add the gelatin.
2
Whisk in 1 3-oz (85 g) package of lime-flavored gelatin and stir for 2 minutes. The combination of gelatin and tonic water is what gives these cupcakes their ghoulish glow. Once your water is boiling, pour in a small package of lime-flavored gelatin, then stir the mixture with a whisk for about 2 minutes. This will ensure the gelatin is completely dissolved.^{[11]
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- You can experiment with different flavors of gelatin, if you'd like!
3
Add 1 cup (240 mL) of chilled tonic water to the gelatin. Up until this point, you've been preparing the gelatin according to the packaging instructions. Instead of pouring in 1 cup (240 mL) of cold water, however, substitute chilled tonic water.^{[12]
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- The tonic water will react to the UV light, which is what causes the cupcakes to glow.
4
Let the gelatin cool for 15 minutes, shaking the pan occasionally. You want your gelatin to be cooled, but not to set up. Let the saucepan sit at room temperature for about 15 minutes. Every so often, shake the pan gently so the gelatin doesn't harden as it cools.^{[13]
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- If the gelatin sets up, you'll have to make a new batch, as it will be impossible to coat the cupcakes.

Part 4

Part 4 of 4:

Dipping and Serving the Cupcakes

1
Remove the cupcakes from the freezer and dip the frosting in the gelatin. Once the gelatin is cool, take your cupcakes out of the freezer. Make sure the frosting is hard to the touch. If it is, hold the cupcake by the base, then dip the frosting into the lime gelatin mixture.^{[14]
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- If you're worried about the cupcakes getting warm while you're dipping them, just take them out of the freezer 2-3 at a time.
- It's fine if a little of the gelatin drips onto the bottom of the cupcake, but try not to saturate the cake or it might fall apart.
2
Return the cupcakes to the freezer for 5 minutes, then repeat 3-5 times. After you finish dipping the cupcakes in the gelatin, return them to the freezer for about 5 minutes. This will allow the frosting time to harden again after getting wet. After about 5 minutes, take the cupcakes out of the freezer and dip them again. Keep repeating this until you've dipped each cupcake a total of 4-6 times.^{[15]
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- Stir the jello after each batch.
- If the gelatin starts to get too thick, you can dip each one 4 times. However, dipping them 6 times will produce a better glow.
3
Keep the cupcakes in the fridge or freezer until you're ready to serve them. Keeping the cupcakes chilled will help them hold their shape until you're ready to show them off. If it will be a day or more before you serve the cupcakes, keep them in the freezer, then transfer them into the fridge about an hour before you're ready to put them under the black light. This will allow the cake to soften before you eat it.^{[16]
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- If you have any leftovers, you can keep them in the fridge for several days.
4
Turn off the lights and place the cupcakes under a blacklight to serve them. In order to get the glowing effect, you'll need to turn off all of the lights. Arrange your cupcakes under or near your blacklight, then flip it on to see them glow! Your guests will be wowed by this simple science trick!^{[17]
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- The glowing effect will be more obvious at night.

Community Q&A

Question

Can I just use regular food coloring or do I have to use a specific kind?

Community Answer

Neon food coloring helps show that green color when the cupcake glow in the dark. It's best to use that type when making the frosting.
Question

Can glow in the dark be made in different colors, or is green the only color?

Qamar

Top Answerer

You can use other colors, but green is the best color, because it shows more easily. The darker the color, the more easily it will be seen.
Question

Do I need black light?

Qamar

Top Answerer

Yes, in order for the cupcakes to glow, you must have black light.