Set Instant Pot to saute; add olive oil, onion, garlic, salt, fennel seeds, oregano, pepper, and red pepper flakes.
Cook, stirring occasionally, until onion is softened, about 5 minutes.
Add red wine; stir to release browned bits. Simmer 2 minutes.
Add tomatoes, bay leaves, brown sugar, and Parmesan rind, if using.
Press Cancel to reset Instant Pot.
Place top on Instant Pot; twist to seal and lock. Turn Steam Release Valve to “sealing.”
Set Instant Pot to cook at High Pressure for 10 minutes.
After cooking is complete, let pressure release naturally (about 10 minutes). After that, manually release the pressure by turning the Steam Release Valve to “venting.”
Remove lid from Instant Pot; hit Cancel to reset.
Stir in vinegar. Taste, and add salt as desired.
If a thicker sauce is desired, set Instant Pot to saute and simmer 10 to 15 additional minutes.
Remove and discard bay leaves and Parmesan rind, if using.
Use immediately, refrigerate up to 3 days, or freeze up to three months.
Notes
When shopping for canned tomatoes for this recipe, I recommend using San Marzano tomatoes. Their flavor is more robust and intense, and they cook down into a lovely rich sauce.
I like to buy cans of whole peeled tomatoes, then crush them with my hands. If you don’t like getting your hands messy, buy crushed tomatoes.
Different brands of canned tomatoes have different amounts of liquid. To account for this variable, I find it best to add the tomatoes to the Instant Pot with their juices, and then simmer the mixture down after pressure cooking if it’s not thick enough to suit your tastes.
If you don’t have every ingredient for this recipe, don’t worry…it will still taste great. No fennel seeds? No problem. Don’t like spicy foods? Leave out the red pepper.
The Parmesan rind is totally optional; I keep a stash of these in my freezer to pop in soups and stews. They release rich savory flavor as the cook; just treat them like bay leaves and remove them after cooking.