Crumble the yeast into a bowl. Add the milk and margarine and stir until the yeast dissolves.
Mix in the sugar and salt. Add the lightly beaten eggs. Add vanilla extract. Work in the flour gradually until the dough no longer clings to the sides of the bowl. Cover with a tea towel and leave to rise for 20 -30 minutes.
Place the dough on a floured worktop and knead until smooth. Split the dough into two equal parts.
Divide one part into 20 slightly larger and 20 slightly smaller pieces and shape them into bunny heads and bodies.
Divide the remaining dough into equal pieces and shape them into ears, front legs and hind legs. Assemble the bunnies on a parchment-lined baking sheet.
Brush the bunnies with lightly beaten egg. Make eyes out of raisins and noses out of hazelnuts.
Leave to rise for 20 minutes in a draught-free place. Bake in the centre of the oven at 200°C for about 15 minutes.
Leave to cool on a wire rack covered with a tea towel. Dust the bunnies with Siúcra icing sugar just before serving.