Gather and prep all ingredients.

Turn the instant pot to "saute" mode and add the bacon into the pot. Cook the bacon, stirring frequently, until crisp. Remove the bacon to a paper towel and set aside, leaving as much bacon fat in the instant pot as possible.

Add the leek, celery, and garlic to the bacon fat. Cook until softened, about 3-4 minutes.

Add the chicken broth into the pot to deglaze the bottom, scraping as needed. Then add the cauliflower and season with salt and pepper to taste. Put the lid on the Instant Pot and set the manual function to high and cook for 5 minutes (this will take additional time to come to pressure).

Once finished, allow the pressure to release naturally. Once depressurized, add in the sour cream and cheddar cheese.

Using an immersion blender, blend until the soup is smooth and has as few lumps as possible.

Optional: Depending on your macro needs, you can add 1-2 scoops of unflavored protein powder here. This can bolster the protein in the macros and also thicken the soup some more.

Serve the soup garnished with bacon and green onion. Enjoy!