Step 1

Cut the pork tenderloin in half so it’s half as long as before

Step 2

If unseasoned, season all sides with salt and pepper

Step 3

Turn on the pressure cooker’s saute mode for medium heat

Step 4

When the display reads hot, add olive oil to coat the bottom of the pot

Step 5

Add pork and cook until golden brown on one side, about 5 minutes

Step 6

Flip to cook the other side for a few minutes

Step 7

Transfer the pork to a plate

Step 8

Add onions

Step 9

Cook for a few minutes, stirring frequently

Step 10

Add water, stirring and briefly scraping up any brown bits stuck to the bottom of the pot

Step 11

Return the pork to the pot, nestling it on top of the onions

Step 12

Close and lock the lid and turn the steam release handle to Sealing

Step 13

Cook at high pressure for 4 minutes

Step 14

Follow with a 10 minute natural release

Step 15

Make sure to wait the full 10 minutes; do not open even if the pressure is completely released before 10 minutes have elapsed

Step 16

Uncover and insert a thermometer into the thickest part of the tenderloin -- it should read 140-145 F

Step 17

Transfer the pork to a cutting board and let it rest, where it will continue cooking

Step 18

Do not slice yet

Step 19

Turn on the saute mode

Step 20

Add heavy cream and mustard to the pot, stirring together

Step 21

Bring to a boil

Step 22

Let the sauce boil for 8-10 minutes to thicken, stirring frequently

Step 23

Stir for a minute to let the boiling subside

Step 24

Stir in parmesan cheese until melted

Step 25

Slice the pork into thin slices and serve onto plates

Step 26

Pour the sauce on top