Preheat the air fryer: Set it to 380°F (193°C). Lightly spray the basket with oil to prevent sticking.
Make the panade: In a bowl, combine breadcrumbs and milk.
Let it sit for 2–3 minutes until the crumbs soften.
Mix the meat: Add ground beef, ground pork, onion, garlic, egg, parsley, allspice, nutmeg, 1 teaspoon salt, and 1/2 teaspoon black pepper to the bowl. Stir gently with a fork or your hands until combined. Don’t overwork it.
Form the meatballs: Scoop into 1 to 1.25-inch balls (about 1 to 1.5 tablespoons each).
You should get 22–26 meatballs. Lightly oil your hands for easier rolling.
Air fry in batches: Arrange meatballs in a single layer with a bit of space between them. Air fry for 9–12 minutes, shaking the basket halfway through, until nicely browned and the internal temperature reaches 165°F (74°C).
Repeat with remaining meatballs.
Start the sauce: In a large skillet over medium heat, melt the butter. Whisk in flour and cook for 1–2 minutes until lightly golden and nutty.
Add the liquids: Slowly whisk in beef broth to avoid lumps. Stir in Dijon and Worcestershire.
Simmer for 3–5 minutes until slightly thickened.
Finish with cream: Lower the heat and whisk in the cream. Simmer for 2–3 minutes until silky. If you like, add a squeeze of lemon or splash of white wine to brighten the flavors.
Taste and season with salt and pepper.
Add meatballs to sauce: Transfer the cooked meatballs into the pan, stirring to coat. Simmer for 2 minutes to marry the flavors.
Serve: Garnish with parsley. Pair with mashed potatoes, buttered egg noodles, or steamed rice.
Lingonberry jam on the side is a classic touch.