Chop the mustard, leaves and tender stems of both greens. Wash thoroughly in several changes of water.
Boil 1 cup water in pressure cooker and drop the chopped greens, ginger, garlic, green chillies and salt.
Pressure cook it for 6 whistles.
Let it cool to room temperature.
Grind it coarsely using a handmixer.
Sprinkle corn meal on the saag and cook for 15 minutes on low heat.
Saute onion in ghee till brown.
Stir in the saag and heat well.
Serve with makki ki roti.