Wash the Peerkangai/ Turai/ Ridge gourd scrubbing itwell. Remove the peel- this is the main ingredient for the thogayal. Reserve the marrow/ flesh of the ridge gourd for other recipes. I do not add the marrow to the thogayal as it makes it too watery, as well as does not give the taste that the peel alone does.
Slice the Peel roughly into about 1" pieces to make them convenient to handle.
To prepare the Pirandai/ bone setter stem: apply sesame oil on your hands when you pluck the stem or otherwise handle the stem. Select young tender digits of stem from the first 2 nodes of the plant. Older stems are tough, fibrous and can cause itching/ irritation when handled or even when consumed.
Slice the Bone setter stem (both peel and marrow) lengthwise and split each half into 1/2" pieces.
Keep all the ingredients ready as in the above list.
Heat oil in a pan, reduce the heat and add methi seeds (menthiyam) and til seeds (ellu) one after the other, sautéing for upto 5 seconds till they crackle.
Add the pepper and hing, sauté.
Add the peanuts, sauté for 30 seconds while the peanuts crack and burst.
Add the moong dhal, sauté for 30 seconds, stir to ensure the dhal doesn't char or blacken.
Using a slotted spatula, remove all the roasted ingredients to a dry bowl, gently pressing them to the side of the frying pan as you remove them, so that as much oil as possible is drained and retained in the pan.
To the remaining oil (add 2 teaspoons of oil if it is not sufficient), add the sliced peel and the bone setter stem pieces.
Add the curry leaves and the turmeric powder. if fresh, the curry leaves will crackle.
Stir well, turning the peel over so that it is coated with the oil. Saute for 3 - 5 minutes on low flame till the bone setter turns pale in colour, and remove the pan from the stove.
Once the roasted vegetables, lentils, peanuts and spices have cooled, grind them into a paste in the food processor, adding as little water as possible, 1- 2 teaspoons at a time. Grind till you get a chutney or pesto like consistency - a little coarse but with all the ingredients ground in.
Add salt sparingly and run the processor again. Taste and add more salt if required.
Transfer the peerkangai thogayal to a serving bowl
Temper with mustard seeds and curry leaves in sesame oil, pour the tempering onto the thogayal.
Serve as a side dish with rice, rasam and poriyal or by itself, mixed with hot rice and ghee.