Mix the yeast, sugar and salt in lukewarm milk, keep aside until the yeast turns foamy.
Meanwhile take the flour, egg, sugar in a large bowl, add gradually the foamy yeast and knead to get a soft dough, now add the butter and knead everything for 10 minutes.
Arrange the dough in a bowl covered with a towel, keep aside for atleast for 2 hours until it doubles in size.
Knead the dough well and divide it in 6 large balls. Divide each balls as small ball, large ball and a medium ball.
Roll the large ball as a rope, while the medium ball as oval shaped ball and small ball as round ball.
Roll the long rope like dough as shown in the picture, cut the oval shape ball in the middle to half of the ball and separate it to make bunny's ears.
Keep the small ball as shown in picture to make the bunny's tail. Arrange the rolled bunnies over the baking tray. Keep the baking tray in a warm place for half an hour.
Preheat the oven to 350 degree F for 5 minutes. Mix the egg yolk with milk for brushing together.
Place a chocolate chip on the head of the bunny to make an eye. Now brush the unbaked bunnies generously. Bake them for 20-25 minutes until the crust turns golden brown.
Cool it completely on a wire rack and enjoy.