Put potatoes in saucepan, cover with cold water and bring to a boil. Reduce heat to medium, put lid on and cook until soft, 10-12 minutes. Drain well and mash. Transfer to a large bowl. Refrigerate until ready to use.
Put grated cabbage and carrot in a saucepan. Add just enough water to cover the bottom of the pan, bring to a boil. Reduce heat to medium, put lid on and cook until soft, 5-7 minutes. Drain well and let cool. Add to potatoes.
Add all remaining ingredients to potato mixture and stir.
Line a baking sheet with waxed paper. Using a metal portion scoop measure mixture onto baking sheet. A scoop that holds 2 tablespoons will make 32 patties.
Heat oil in large frying pan on medium-high heat. Fry potato cakes until well browned, about 3 minutes per side. Add more oil as needed.
Top with sour cream and green onions. Serve.
Notes
*Grated onion is essential as finely chopped onion doesn’t have time to cook fully.