Preheat oven to 400°.
In a large bowl, soak breadcrumbs with ⅔ cup milk for 10 minutes.
Meanwhile, heat 2 tablespoons butter in a small sauté pan and cook the onion over medium heat until softened, about 5 minutes. Remove from heat and cool slightly.
Add the ground beef, salt, nutmeg, paprika and beaten eggs to the breadcrumb mixture along with the cooled onion. Mix well.
Using a small cookie scoop or 2 spoons, form small balls out of the meat mixture and place on parchment-lined baking sheets.
Bake the meatballs for 12-15 minutes until brown.
In a large sauté pan or skillet, melt the remaining 2 tablespoons of butter over medium heat. Add the meatballs to the pan and sprinkle with the flour. Cook, stirring, for about 5 minutes until all of the flour has been absorbed.
Slowly pour the 1 cup milk into the pan, stirring constantly but carefully so that the meatballs do not break apart.
Reduce the heat to low, cover and cook for about 5 minutes, stirring occasionally.
Uncover the meatballs and stir, adding a little more milk if needed for a thinner sauce. Season to taste with salt and white pepper. Serve the meatballs sprinkled with parsley or chives alongside potatoes, lingonberries and pickled cucumbers.