To toast the coconut, preheat the oven to 150 °C and line a baking tray with baking paper. Spread the coconut over the tray and bake until it starts to change colour (about 5-7 minutes). Watch carefully so it doesn’t burn and stir it around a couple of times. Set aside to cool.
To make the buttercream, beat the butter and icing sugar until it is noticeably paler (this takes about 5 minutes with a stand-mixer on high, or 10 minutes with an electric hand-mixer on high).
Scrape down the sides and add the boiling water and vanilla or lemon juice and beat for another 5 minutes.
Fill a piping bag with the buttercream and snip off a 1 cm wide opening.
Starting from the middle, pipe a spiral on the top of your cupcake to completely cover the top. Pipe a ring around the outside to create a nest shape.
Gently press toasted coconut into the buttercream, covering it completely, and fill the centre of the nest with small eggs.
Will keep in an airtight container for up to three days.