Turn on your Instant Pot and set it to ‘Sauté’ mode. Pour in the olive oil and let it heat up for a minute.
Add the finely chopped onion to the pot. Sauté for about 3-4 minutes, stirring occasionally, until the onion becomes translucent and soft.
Toss in the minced garlic and continue to sauté for an additional 30 seconds, just until the garlic becomes fragrant, but be careful not to let it burn.
Pour in the fire-roasted diced tomatoes along with their juices, the vegetable broth, sugar, dried oregano, and a generous pinch of salt and pepper. Stir everything well to ensure it's evenly combined.
Secure the lid on the Instant Pot, ensuring the valve is set to ‘Sealing’. Select ‘Manual’ or ‘Pressure Cook’ and set the cooking time for 10 minutes.
When the cooking cycle is complete, allow the Instant Pot to naturally release pressure for 10 minutes. Then, carefully switch the valve to ‘Venting’ to release any remaining steam.
Once safe to do so, open the lid and use an immersion blender to purée the soup until it’s beautifully smooth. If you don’t have an immersion blender, carefully transfer the soup in batches to a countertop blender, blending until silky.
Stir in the heavy cream (or coconut milk) and add the fresh basil leaves. Give the soup a quick blend again to incorporate the basil flavor.
Taste the soup and adjust the seasoning as necessary. If you prefer a hotter soup, simmer it on the ‘Sauté’ setting for an additional 2-3 minutes to warm through.
Ladle the creamy tomato basil soup into bowls and garnish with additional fresh basil leaves for a vibrant touch. Serve hot and enjoy!
Notes
Drizzle a swirl of extra cream on top of each bowl and sprinkle with cracked black pepper for visual appeal. A rustic piece of bread on the side makes for a charming presentation.