Add cans of tomato, garlic, and broth to an instant pot and mix well.
Stir in oregano, salt, and pepper and mix well.
Place top on the instant pot and seal.
Close the pressure release valve. Set the instant pot to manual, high pressure for 10 minutes. Quick release the steam when the cooking cycle is done.
Open the pot and stir in sugar. Add butter and stir until melted. Stir in basil. Use an immersion blender to blend the soup smooth. Stir in half and half and serve.