In a bowl, mix flour, coffee and baking soda well. Mix in powdered jaggery.
Cut butter into small cubes and work it into flour with finger tips until you get a sandy texture.
Make a well and add in the whisked egg and vanilla extract.
Mix it all together to get a dough, adding 1-2 tsp milk if needed.
Gently work in the chocolate chips.
Divide into 12 portions. Roll into balls, flatten lightly, arrange on a baking tray. Leave at least 1 inch space between the cookies. bake in a preheated oven at 180C for 12-14 minutes.
Remove and cool on a wire rack for 10 minutes. Store in airtight container.
Notes
If you have flattened the cookie too much then baking time may be lesser.The cookies will continue to crisp up as they cool.