Press the Sauté button and allow the Instant Pot to heat up.
Drizzle a bit of olive oil into the inner pot of your instant pot.
Add in the chopped onions, garlic, red chili flakes, oregano, basil and cook until fragrant, about 2-3 minutes.
Add in the penne pasta, then pour the water and sprinkle the salt.
Pour the purred tomatoes on top of that, covering as much of the top layer of pasta as you can, and don't stir.
Secure the lid, and move the steam release valve to Sealing. Use the Manual or Pressure Cook button on your machine to cook at high pressure for 5 minutes.
When the cooking is complete, do a Quick release.
Stir the cooked pasta, mixing the sauce throughout evenly.
If the pasta looks a little watery at first, stirring the pasta will help the rest of the water absorb.
Season to taste if needed, sprinkle some cheese and chopped basil . Serve warm with Crusty bread.