Turn the Instant Pot to “Sauté” function. When the pot is hot, add bacon and cook until just crispy (about 5 minutes). Remove bacon with a slotted spoon and set aside to use as a garnish on top of the soup later.
Leave bacon drippings in the pot.
Add onion, carrots, celery, and garlic to the pot with the bacon drippings. Sauté just until the onion is translucent (about 3-5 minutes). Turn off the pot.
Add lentils, chicken stock, tomatoes, cumin, paprika, thyme, salt, pepper and bay leaf. Secure the lid on the pot. Close the pressure-release valve. Select “manual” and set the pot at “high” pressure for 6 minutes. It may take the pot up to 25 minutes to come to pressure and start cooking.
At the end of the cooking time, allow the pot to sit undisturbed for 10 minutes, then release any remaining pressure.
Stir well to combine.
Remove bay leaf. Taste the soup and season with additional salt and pepper, if necessary. Use an immersion blender to puree a small portion of the soup (about 3 pulses should be fine), or transfer 2 cups of soup to a regular blender and puree. Stir.
Serve in individual bowls and top with crispy bacon and fresh parsley.