Make the meatballs: peel, chop and boil the potatoes. Let them cool and then mash them well.
Chop the onion very finely. Cook it in 2 Tbsp. of butter until it is beginning to brown. Let the onion bits cool.
In a large bowl, break up the meat; pile in the potato, onion, egg, milk, salt, pepper and breadcrumbs. Mix carefully — get everything just incorporated, and don’t squeeze it through your fingers!
If it’s too dry, add up to half a cup of water a tablespoon or two at a time. Roll into balls (I like around 16) and set aside.
Make the potatoes: put a bigass pot of water on the stove. Salt aggressively. Peel and chop the potatoes. Dump them in the water and turn on the heat.
Bring them to a boil and cook until a knife poked into a large piece goes in easily.
Drain, dump the butter in, stir, and cover.
Start the cream sauce: melt butter in a pot and stir in flour. Cook for a moment until it’s bubbly and smells like toast.
Add the beef broth slowly, whisking to make sure the roux doesn’t lump up; once the broth is mixed in, add the half and half and heavy cream.
Add soy sauce and white pepper and set over low heat.
Cook the meatballs: Melt some butter in a large skillet. When it bubbles, add in your meatballs. Let them brown on one side and then turn them.
Keep turning the meatballs while frequently stirring the cream sauce. You want the meatballs cooked through and the sauce pleasantly thick.
Taste for salt once the sauce starts to thicken.
Serve meatballs and potatoes both slathered in sauce, with a healthy spoonful or two of lingonberry jam.
