Prepare the Paste: In a mortar and pestle or a mixer grinder, crush together the dry coconut, garlic, 1/2 inch ginger, and fresh coriander leaves to make a coarse, rustic paste.
Heat the Oil: Heat 1/2 ladle of cooking oil in a pan or kadhai over a medium flame.
Add the Spices: Once the oil is hot, add the mustard seeds, cumin seeds, asafoetida, and curry leaves. Let them pop and crackle in the oil.
Fry the Onions: Add the chopped onion to the pan and fry lightly until it turns a soft golden brown colour.
Cook the Paste: Stir in the prepared coconut-garlic-ginger-coriander paste and roast it well for about 1 minute.
Add Tomatoes: Put the chopped tomato into the pan and cook until it turns soft and mushy.
Add Dry Masalas: Lower the flame to prevent the dry spices from burning. Add the Kanda Lasun Masala, garam masala, turmeric powder, and salt to taste. Mix everything well.
Add Ridge Gourd and Peanuts: Stir in the roasted peanut powder and the chopped ridge gourd pieces. Mix and cook this Maharashtrian Ridge Gourd Curry base for about 2 minutes on a medium flame.
Add Water: Pour 2 1/2 cups of warm water into the pan and give it a good stir.
Cook and Serve: Cover the pan partially with a lid and let the curry cook gently on a low flame for about 20 minutes, or until the ridge gourd is completely soft. Turn off the heat and serve your delicious curry hot!