Wash the French beans and cut them into small pieces.
Wash, peel the potatoes and cut them into small wedges.
Place the cut beans and potatoes in a small bowl and steam them in pressure cooker.
If you want to retain the green color of the beans (as I have done), a pinch of turmeric powder can be mixed in with the veggies.
Cook the beans for about 4 to 5 whistles and allow it to cool naturally. When cool, blend the vegetables to a smooth paste.
Melt butter in a pan and add it to the puree. You can also use olive oil instead. Season to taste. You can add any spice of your choice, though jeera combines well with these vegetables.