Preheat your oven to 350°F (175°C) and line a cupcake pan with colorful cupcake liners.

In a large mixing bowl, combine all-purpose flour, granulated sugar, baking powder, baking soda, and salt and whisk until well blended.

In another bowl, mix together eggs, melted butter, vanilla extract, milk, and Greek yogurt until smooth.

Gradually pour the wet ingredients into the dry ingredients, folding gently until no dry flour remains visible.

Mix in tonic water until the batter glows slightly.

Pour the batter into the lined cupcake pan, filling each liner about ¾ full.

Bake for 18-20 minutes, or until a toothpick inserted comes out clean.

Let the cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

While cooling, prepare frosting by beating softened butter, then gradually mix in powdered sugar, vanilla, and tonic water until smooth.

Frost cooled cupcakes with a piping bag and sprinkle with edible glitter if desired.