In a large mixing bowl. combine meatball ingredients with your hands until just incorporated. Do not overman.
Rolling with wet hands, make each meatball about the size of 1 tbsp. Stuff each meatball with a mozzarella pearl, and roll closed. Set aside on a parchment lined sheet or tray until all meatballs are stuffed and formed.
In a large, deep non stick frying pan or cast iron skillet, heat olive oil over medium high heat, for 2-3 minutes until nice and hot. Working in batches, add meatballs to the skillet and brown the meatballs on both sides, about 3-4 minutes a side. Set aside on a plate and continue until all meatballs are browned. (Meatballs will cook through in the sauce later.)
Reduce heat to low, add half the butter (2 tbsp) to the pan and melt.
Add garlic and cook until just fragrant, about 30 seconds.
Whisk or stir in flour until well incorporated.
Slowly whisk or stir in wine, followed by chicken stock, lemon juice, and caper brine.
Add the meatballs back to the pan bring heat to medium.
Cook for 6-7 minutes, stirring occasionally, until sauce is thickened, and meatballs are cooked through.
Turn off heat, stir in reserved butter until melted, then stir in capers.
Serve with fresh parsley.