Trim as much fat off the pork as you can, and cut it into 4 inch chunks. I used a 3-pound pork shoulder and after trimming the fat and cooking I ended up with about 2 pounds of meat. Season with salt and pepper (use 1 teaspoon of salt and pepper for this step).
Turn the saute mode on on the Instant Pot (I used the Instant Pot DUO 6) and let it get good and hot. Add the olive oil and sear the meat for two minutes on two sides. (You may need to do this in two batches.) Remove the pork and set it aside in a large bowl.
Add the onions and a splash of chicken stock to the pressure cooker, loosen any brown bits from the seared pork, and saute for 3 minutes.
Add the garlic and a cup of white wine (chardonnay) and allow it to saute for 2 minutes.
Next, add the rest of the chicken stock, fresh herbs, dried porcini mushrooms, shiitake mushrooms, remaining 1 1/2 teaspoons of salt and pepper, and the seared pork. Put the lid on the IP and pressure cook it for 17 minutes. Then do a natural pressure release for 15 minutes, and release the rest of the pressure manually. (The IP took 13-15 minutes to come to pressure and about 3 minutes to release the rest of the pressure from the pot.)
When the pressure cooker is depressurized, remove the meat and set it aside. Then strain any fat that is visible off the top.
Turn the IP to saute mode and let it come to a boil. Add the carrots and rigatoni pasta and let simmer for 10 minutes. (That was 2 minutes less than the package stated for al dente pasta.)
While the rigatoni is cooking, shred the pork.
Next, turn the Instant Pot off and stir in the Parmesan cheese and cream.
Remove the inner pot from the pressure cooker and set it on a pot holder on the counter so the pasta doesn’t continue to cook. Fold in the meat and parsley and served this yumminess with a garnish of more fresh chopped parsley and grated Parmesan cheese.