Press the saute button on the instant pot. Once it displays hot, add oil, whole black cardamom, and bay leaf to it. Saute for 30 seconds. These whole spices add a depth of flavor to this masala. (Step by step pics above in the main post)
Stir in the sliced onions along with ginger and garlic.
Add the chopped tomatoes. Pour in the water and mix to combine.
Close the lid and seal the pot. Cancel the ‘Saute‘ mode and press the ‘Manual or Pressure Cook‘ button. Cook on HIGH PRESSURE for 10 minutes. Make sure that the pressure release valve is in place, and is set to the Sealing position.
After the Instant Pot beeps, allow the steam to release naturally (NPR). After the pin drops, carefully open the lid.
Remove the whole spices: black cardamom, and bay leaf from the insert. With an immersion blender, blend the cooked ingredients until smooth.
Press the saute button on the Instant Pot and simmer the pureed masala for 10-15 minutes or until the oil separates. Keep stirring occasionally. (Step by step pics above in the main post)
Let the onion tomato masala cool completely. Transfer it to a canned jar or airtight container and refrigerate. Stays well for up to two weeks in the refrigerator.
Use the masala as directed in your recipes.