Set the Instant Pot in saute mode and add butter.
Once it melts, add bay leaf and garlic. Saute for one minute.
Add onions and saute for 4-5 minutes, until it begins to brown.
Add the frozen spinach, garam masala, salt, and pepper.
Add the vegetable stock. Mix well and deglaze the pot.
Secure the IP lid, cancel the saute mode and set it to pressure cook mode for 5 minutes.
Once the Instant Pot beeps, do a quick release of pressure.
Take the bay leaf out of the soup. Blend it using an immersion blender until it is smooth.
In a small bowl, combine the cornstarch with ¼ cup of water. Mix well to form a slurry.
Set the Instant Pot back to saute mode.
Add the cornstarch slurry to the Instant Pot along with the cream.
Simmer for 2-3 minutes.
Serve hot with breadsticks or grilled cheese.