Chop 100 g chocolate. Bring the cream to the boil, remove from the heat, stir in the chocolate and let it melt. Pour the chocolate cream into a mixing bowl and chill for 2-3 hours.
Knead lemon zest, butter in flakes, 90 g icing sugar, egg and flour first with the dough hooks of the hand mixer, then with your hands to a shortcrust pastry. Wrap the dough in foil, chill for about 1 hour.
Roll out the dough in portions on a floured work surface to a thickness of about 0.5 cm, cut out a total of about 50 rabbits and eggs. Knead the remaining dough again and again and roll out again. Put the cut out biscuits on 2 baking trays lined with baking paper.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 10 minutes one after the other, remove from oven and let cool on a cake rack.
Briefly whip the chocolate cream with the whisks of the hand mixer, fill into a piping bag with a small perforated spout. Spray chocolate cream on about half of the biscuits, place the other half on top.
Put the biscuits in a cool place for about 1 hour.
Chop 25 g chocolate and melt over a warm water bath. Sift 100 g icing sugar and mix with 2 tablespoons of water, divide into 4 portions and colour differently with food colouring. Pour the chocolate and icing into piping bags with small perforated spout.
Decorate rabbit cookies with chocolate. Decorate egg biscuits with icing. Leave the biscuits to dry in a cool place for at least 2 hours. Store them in a cool and dry place and consume them promptly.