Place the liner into the instant pot and set the pot on sauté.
Add the butter, diced onion and garlic. Cook for 3-5 minutes until onions are beginning to soften.
Press cancel, then add the Italian seasoning, broth, fire roasted tomatoes and gnocchi. Give it a gentle stir to make sure the gnocchi is submerged.
Place the lid on the pot, turn the valve to seal and set the pot on high pressure for 1 minute.
When the timer is complete turn the valve to vent the pressure. When the pin drops carefully remove the lid.
Press cancel and set the pot to sauté. Stir in the heavy cream and bring to a gentle boil while stirring. Cook for 3-5 minutes until the soup begins to thicken add salt and pepper, if needed, then serve garnished with fresh chopped basil.
Notes
We've chosen fire roasted tomatoes for this recipe as they are richer in flavour than regular diced tomatoes and less acidic. If you can only find regular diced tomatoes you can use those if you prefer, you may want to add 1 teaspoon of granulated sugar to help balance the acidity.
You do not need to add any flour or corn starch to this recipe as the starch from the gnocchi will thicken the soup. If it is too thin for your liking after cooking, set the pot to keep warm and let it sit for 5-10 minutes prior to serving, it will continue to thicken as it sits.
After refrigeration the soup will be quite thick. You can add a bit of broth before reheating to thin the soup if you prefer.