Set Instant Pot to saute. Add butter to pot. Once it has melted add the onion and minced garlic. The lid stays off for this portion.
Saute onions and garlic for 3 minutes. Turn pot off.
Add the fire roasted tomatoes, chicken broth and tablespoon of basil.
Secure and lock the lid. Make sure the lever is set to seal.
Press the manual button and set to 5 minutes.
Once it is done cooking, use the quick release. Once the steam is released carefully remove the lid.
Use an immersion blender to puree the soup. If you don’t have an immersion blender you can use a regular blender, just let the soup cool down before putting it in the blender.
Stir in the fat free half and half. Garnish with additional basil if desired.