Add potatoes and 1 cup water to insert. Lock lid. Set valve to sealing. Program for manual-high and 15 minutes. Drain.
Add sour cream, gouda, green onions, butter, parsley, pepper, and salt. Mash with potato masher or fork until coarsely mashed. Potatoes will be lumpy. Garnish with extra green onions, if desired.
Stovetop
Add potatoes to medium saucepan. Cover with water. Bring to a boil. Boil 20 minutes. Drain.
Add sour cream, gouda, green onions, butter, parsley, pepper and salt. Mash with potato masher or fork until coarsely mashed. Potatoes will be lumpy. Garnish with extra green onions, if desired.