Add onions, carrots, celery, garlic, lentils, and tomatoes to your Instant Pot.
Season ingredients with basil, thyme, oregano, salt and pepper.
Add broth and stir to combine.
Set instant pot to MANUAL/PRESSURE COOK on High for 15 minutes. Once the pressure cooker is done, quick release. Remove lid and stir in spinach.
STOVETOP INSTRUCTIONS
Add all ingredients to a dutch oven and bring to a boil over medium high heat. Reduce heat to simmer, then cover. Cook for about 25-30 minutes.
Notes
Broth substitution: If you don't have vegetable broth on hand and are not vegetarian, you can always use chicken broth instead.Storage: This lentil soup can remain refrigerated in an airtight container for 3-4 days, or in the freezer for up to 3 months.Which size Instant Pot should I use for this recipe? I make this in my 8-quart Instant Pot Duo, but you could also make this in a 6-quart pressure cooker. Do not attempt to make this in a 3-quart pressure cooker.