crush the ginger,garlic & green chillies(w/o water) to form a coarse paste.

heat oil in a saucepan.when hot add the cinamon stick.wen it colors a little,add the ginger-garlic-chili paste

saute for a min,add the chopped onions.saute them until they turn golden brown.

now add the coriander powder,cumin powder,turmeric powder,red chili powder,salt.add a teaspoon of water(this is 2 avoid the burnin of the spices) & cook for a min,keep stirrin

now add the tomatoes,add half cup water & cook until the tomatoes turn mushy & the water is almost evaporated.stir occasionaly

now add the potatoes,half of the coriander & the remainin water.bring to a boil.add a little more water,simmer for 5 min.

remove from heat,add the garam masala & lemon juice.mix well.cover & let rest for 2 min.

garnish with remainin coriander leaves & serve