Chop the onion finely and crush the garlic. Heat 1 tbsp of the oil and sauté the onion until it's soft. Add the garlic and sauté for another minute. Cool slightly.
Peel the apple and grate the flesh (not the core) into a large mixing bowl. Be careful not to grate your fingers, too!
Tear the bread into small pieces (or use white bread crumbs) and add it to the bowl. Leave the bread and apple to stand for 5 minutes.
Now add the Parmesan, egg yolk, ground pork or chicken, sautéed onion and garlic, parsley, Worcestershire sauce, tomato paste, honey, and nutmeg.
Season with a little salt and pepper, then use your hands to mix everything together thoroughly.
Scoop up the meat mixture with a teaspoon and roll it into meatballs. Dust them with flour.
Heat the remaining oil in a nonstick frying pan over medium-high heat and brown meatballs in batches for 2 to 3 minutes, turning regularly. Drain on paper towels.
For the sauce, melt the butter and stir in the flour. Remove from the heat and whisk in the broth, a little at a time. Then add the cream, soy sauce, and Worcestershire sauce. Return to the heat and bring to a boil, stirring constantly. Add the meatballs.