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

In a large mixing bowl, combine the cupcake batter ingredients and beat on low for 30 seconds, then medium for 1 minute.

Fill each cupcake liner about ¾ full, then bake for 20–25 minutes, checking for doneness with a toothpick.

Remove from the oven and cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

For the frosting, beat softened unsalted butter until creamy, then add icing sugar and milk until smooth.

Divide the frosting, mixing green food coloring into one bowl for the 'grass' and keeping the other chocolate.

Pipe the green frosting onto the cooled cupcakes, then swirl on the chocolate frosting to form nests.

Garnish each nest with 3–4 whole Cadbury mini eggs.