When butter melts, stir in the onion and cook 1-2 minutes, or until onion is beginning to soften.
Add kielbasa, and cook until it is starting to brown, stirring regularly.
Add cabbage, salt, and pepper, and cook 5-10 minutes, or until cabbage has wilted, stirring occasionally.
Add chicken broth, and scrape up any browned bits from the bottom of the pot.
Add the egg noodles and press them down into the broth but don’t stir in.
Close and lock the lid. Press manual high pressure and adjust the cooking time to 6 minutes. It should take about 10-15 minutes to come to pressure.
When the cooking time has finished, carefully turn the pressure release valve to venting to release the pressure.
Unlock the lid and give everything a good stir. If the noodles aren’t done, set the lid on while you make the sauce.
If making the sauce, stir the sour cream, mustard, mayonnaise, horseradish, and salt together until well combined.
Serve with the sauce and sprinkled with fresh parsley.
Notes
Butter: I like to use salted butter, but you can use unsalted butter and season with salt to taste at the end.
Onion: Either white or yellow onion will work.
Kielbasa: The sizes keep changing on kielbasa packages, so use the size listed as an approximation of what you'll need.
Noodles: It's important to use wide egg noodles. The narrower egg noodles will cook in less time, and you'll end up with overcooked pasta.
Horseradish: This is ground horseradish root, not prepared horseradish sauce. If you'd prefer to use the prepared horseradish sauce, omit the mayonnaise or additional sour cream and slightly decrease the amount of sour cream.