Preheat over to 180°C/350°F/Gas Mark 4 and grease a round cake tin
Pour yoghurt into a bowl with the 3 eggs and caster sugar. Beat together until fluffy.
Fold the flour and baking powder into the mixture. Stir everything until the mixture is smooth and then mix in the vegetable oil.
Pour your mixture into the cake tin and pop into the oven for 40 minutes. Then remove the cake from the tin and place on a wire rack and allow to cool.
While the cake is cooling, make your icing. Melt the chocolate and allow to cool slightly. Then add the butter, vanilla extract and salt. Beat with an electric mixture for a few minutes until the mixture is light and airy.
Slow down the mixer and add the icing sugar, one spoonful at a time. Leave the mixer on for a few minutes and then add the eggs, again one at a time. Beat for a few more minutes. Then add the melted chocolate and mix for another few minutes.
Cut the cake in half horizontally once it is cool. Make sure that the bottom half is thicker than the top half. Separate the two halves and cut a circle out of the middle of the top half. You can use a small bowl or large glass to guide you. This hole will make the nest for the mini eggs.
Spread some of the chocolate icing on the bottom half of the cake and then place the other part on top.
Spread the rest of the icing all over the cake and put the chocolate eggs and chick into the nest.