Place the drained potatoes in a large bowl, and use a potato masher to mash them up good n’proper. Add the sauteed cabbage mixture and the non-dairy cream, and stir thoroughly. If you like, you can use an immersion blender to puree 1/3 of it or so and then use a spoon or spatula to combine it all into a rich, creamy, delicious mess. Add salt and pepper to taste, and garnish with the remaining chopped onions, and even some shredded raw cabbage.