1/4tspsaltoptional, I suggest seasoning when it is done
Dice your leftover corned beef into small bite size pieces. Add this, your diced onion, frozen mixed vegetables and beef broth into your pressure cooker. Can add salt now, I choose to season at the end (some corned beef and broth already has a lot of salt in it)If cooking on a pot on your stovetop put on medium heat.
Set your pressure cooker to high pressure for 2 minutes. Allow to naturally release for 5 minutes, then let out rest of steam.If making on the stovetop allow it to come to a rolling boil stirring it until the vegetables are as soft as you'd like and meat has softened.
Whisk together your whipping cream and cornstarch in a separate bowl until all lumps are gone.
Turn your pressure cooker off, then press saute and wait until it begins to bubble. Pour your cornstarch mixture in and allow to bubble for about 2 minutes, stirring, so chowder/soup thickens. Serve!If making on stovetop add cornstarch mixture once your vegetables are softened to your desired texture, stir until it is as thick as you want it. Remove from heat and serve immediately.