Add the oil and onions to the pot. Cook for 7 minutes, stirring occasionally.
Cancel the saute setting.
Add the carrots, potatoes, vegetable broth, garlic, salt, pepper, celery seed, paprika, dry mustard and thyme to the instant pot.
Place the lid on and set the vent to seal.
Cook on high pressure for 10 minutes. Quick release the pressure when cooking is finished.
Open the lid. Using an immersion blender, puree the potatoes. If you like chunks of potato in the soup, only puree half of the potatoes.
Add the milk, lemon juice and nutritional yeast to the potatoes. Stir well.
Add salt & pepper to taste.
Serve immediately or keep warm in the instant pot with the Keep Warm setting.
Notes
Store in an airtight container in the fridge for up to 5 days, or in the freezer for up to 3 months. Reheat over medium heat on the stove for 5 minutes, or in the microwave on 80% power in 30-second increments.