Prepare the Cupcake Batter

• Preheat your oven to 350°F (175°C) and line a cupcake tin with liners. In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.

Cream the Butter and Sugar

• In a separate large bowl, beat the butter and sugar together until light and fluffy, about 2-3 minutes. This step is crucial for making the cupcakes airy and soft.

Add the Wet Ingredients

• Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

Alternate Dry and Wet Ingredients

• Mix the tonic water and milk together in a cup. Gradually add the dry ingredients to the butter mixture, alternating with the tonic water/milk mixture. Begin and end with the dry ingredients, mixing until just combined. Be careful not to overmix!

Color and Layer the Batter

• Divide the batter into separate bowls and add different neon food colorings to each. Spoon layers of different colors into the cupcake liners to create a marbled or layered effect.

Bake to Perfection

• Bake the cupcakes for 18-20 minutes or until a toothpick inserted in the center comes out clean. Let them cool completely before frosting.

Making the Glow-in-the-Dark Frosting

Beat the Butter

• In a large bowl, beat the butter until smooth and creamy.

Add Powdered Sugar Gradually

• Slowly add the powdered sugar, mixing well after each addition.

Incorporate the Glow Effect

• Pour in the vanilla extract and tonic water, then continue beating until light and fluffy. The tonic water will add the glowing element to the frosting.

Add Color and Decorate

• For extra vibrance, add neon food coloring to the frosting. Pipe or spread onto the cooled cupcakes using your favorite technique.