Heat a large skillet over medium-high heat. Add the meat and cook, breaking up with a spatula, until browned. Transfer the meat to the Instant Pot. Discard excess grease left in the pan.
In the same skillet, melt the butter with the olive oil. Add the onions and cook, stirring, until softened, about 5 minutes. Add the garlic and cook, stirring, for another 30 seconds. Transfer the mixture to the Instant Pot.
Add the mushrooms to the skillet and add a pinch of salt. Cook, stirring occasionally, until softened and beginning to brown, about 5 minutes. Transfer to the Instant Pot.
Add the tomato sauce, tomato paste, Worcestershire sauce, salt, pepper, and parsley, if using.
Cover the pot, set the valve to the sealing position, and pressure cook for 1 hour.
When the cooking time is up, quick-release the pressure.
Serve immediately over cooked pasta.
Notes
1. You can use a combination of beef and pork if you like.2. I use a large skillet to brown the meat and saute the vegetables. You could do this directly in the instant pot, but I find it is easier to do it in a large skillet.3. Store leftovers in the refrigerator for up to 3 days or in the freezer for up to 3 months.