Chop cooking chocolate coarsely and transfer it to a heat proof bowl placed over a sauce pan of simmering water. Add butter and melt it until creamy and saucy as shown below. Cool down to room temperature.

Beat egg and sugar until thick, pale and fluffy. Add vanilla essence and beat it once. When you slowly raise the beater, the batter will fall back into the bowl in slow ribbons, that is the correct consistency. Add it to melted chocolate butter mixture and whisk it well until even mixing. Set aside.

In a separate mixing bowl whisk together maida, baking powder and salt. Now add this mixture to the chocolate mixture and mix well. It will be sticky at this stage.

Cover with a silver foil / plastic wrap and chill it for at least 3 hours or overnight is best. It should be firm when you touch and see. Preheat oven to 165 deg C for 10 minutes. Now the dough is ready to use.

Meanwhile use a tablespoon to scoop out the dough then shape it into balls and roll each ball into icing sugar.

Make sure it is completely coated so that no chocolate dough is shown outside. Do this for the entire dough. Lay a parchment paper in the baking tray and line the cookies about 1.5 inches apart. Bake them at 165 deg C for 8-10 minutes. Mine got done in exactly 10 minutes. The edges will be slightly firm but the center will be slightly soft that is correct texture for chewy cookies. Do not overbake till crispy. Remove from oven and cool down in wire rack.

Serve it warm or at room temperature. Store in airtight container and enjoy!