Preheat the oven to 350ºF. Add 12 cupcake liners to a 12-hole cupcake pan. 

Put the butter and sugar into a large mixing bowl and use an electric handheld whisk to beat together until light and fluffy. 

Add the eggs and vanilla and beat until the mixture is well combined. 

In a separate bowl, whisk together the flour, baking powder, and salt, then add it to the wet ingredients. Use a spatula to fold it into the batter gently. 

Pour in the milk and fold through until combined. 

Divide the cupcake batter between the 12 cupcake liners, filling them 2/3 full. 

Bake in the center of the oven for 18 minutes or until the cupcakes have risen and are a pale golden brown color. When properly baked, they will feel springy to the touch. 

Remove the pan from the oven and transfer the cupcakes to a wire cooling rack. 

Once the cupcakes are cool, pipe the buttercream on top of each cupcake. 

To add a speckled effect, mix the cocoa powder and vanilla in a small bowl, then dip a small, clean paintbrush into the mixture and flick it onto the frosting using your finger. 

For a final garnish, add 3 mini candy-coated Easter eggs to the top of each cupcake. 

Serve and enjoy!