Add one cup of water, chopped mangoes, and slit green chili into a saucepan or kadai. Cook this mango mix over medium heat until the mangoes are soft and tender. It usually takes about 5 to 7 minutes.
While the mangoes are cooking, prepare the spice paste. Grind the ingredients given under "To grind" by adding 2 to 3 tbsps of water and set aside.
When the mangoes are soft and tender, add the ground paste and salt.
Mix well. Simmer this over medium-low heat (2 to 3 minutes), and when it starts to boil, turn off the heat—no need to bring it to a full rolling boil.
Beat/whisk the yogurt (refer notes) and add it to the pulissery. Mix immediately and make sure the yogurt doesn't curdle.
In a separate tadka pan, heat the coconut oil and add the mustard seeds, fenugreek seeds, red chilies broken into pieces, and curry leaves. As they start to splutter, add it to the pulissery mix.
That's it. Yummy pulissery is ready. Serve hot with rice.
Notes
Instead of adding red chili powder and turmeric powder while making the ground paste with coconut, you can add them while cooking the mangoes in the first step.
Adjust the salt and spice according to your preference.
Tempering in coconut oil gives an authentic and unique flavor, but you can also opt for regular cooking oil.
You can add one or two shallots while preparing the spice paste.
You don't need to cook again after adding the yogurt. If needed, simmer for 40 to 60 seconds over low heat.
If you are using store-bought, make sure you blend it smooth before adding it to the curry. I used homemade yogurt, and it was not creamy like the store-bought one. I used a hand churner and whisked it roughly. Further, when mixed with the curry, it blended well.