Using a blender, grind together mustard seds, red chilies, cinnamon stick, cumin, cloves. Add turmeric to the ground spices and keep aside.
In the same blender jar, blend together the tamarind paste, garlic cloves, ginger, vinegar and salt, until it forms a slurry. You can add a couple of tablespoons of water to make it a smooth slurry.
In a large mixing bowl, add the cleaned pork pieces, and mix it well with the spice powders and the slurry of the marinade. Keep the pork in the fridge to marinate for at least 30 mins.
Turn on the IP and hit 'Saute' mode.
Once hot, add the chopped onions and 1 teaspoon mustard seeds
Sauté the onions for 7-8 minutes, until they caramelise.
Hot Cancel, and add the marinated pork pieces to the browned onions.
Add 1/2 cup of water. Add the crushed or grated jaggery and mix well. Deglaze the Instant Pot to make sure there is nothing stuck to the bottom of the Instant Pot.
Pressure Cook for 15 minutes. Once the cooking cycle is complete, let the pressure release naturally for 5 minutes. Then manually release pressure by opening the vent.
Once the pressure is released, open the Instant Pot, and give the curry a mix.
Hit Saute mode and let the curry simmer for 5 minutes to reduce the sauce. Once the sauce has thickedd a little, hit Cancel. Serve the vindaloo with basmati rice or pav bread