To make the masala, take 1 tsp oil in a pan. Once it turns hot, add urad dal, chana dal, dhaniya, peppercorns, fenugreek seeds, white sesame seeds. Roast them in low heat until they turn slightly brown in colour. Next, add the dry red chillies (refer notes 3) and roast until they turn aromatic. Make sure to roast the ingredients in low heat.
Once the roasted spices cool down, add grated coconut (refer notes 4), some water and blend to a smooth paste.
Set this paste aside.
Peel and chop the raw mangoes to small pieces. You can either chop it fine or slightly bigger, depending on your wish. In a thick bottom pan, take 1 tsp oil. Once it turns hot, temper with mustard seeds, turmeric powder, curry leaves and asafoetida.
Next add in the chopped raw mangoes, and about 1/2 cup water and let the mangoes get cooked well and turn soft. If required, add more water.
Once mangoes are cooked well, add the ground masala. Mix well and add about 3/4th cup water, jaggery and salt. Let this simmer in medium heat for 8 to 10 minutes. If gojju is getting thick, add more water and make sure to stir it in between.
Check for salt and spice. If you wish to, you can add more jaggery and turn off the heat.
Serve mavinakayi gojju with akki rotti, chapati, dosa, idli or rice.