Gravy (for a whole batch; reduce amounts if cooking fewer meatballs)
4 tablespoons butter, divided
3 tablespoons flour
3 cups chicken or beef broth
1/4 cup heavy whipping cream
Combine all meatball ingredients in the bowl of a stand mixer. Mix with paddle attachment until very smooth. Alternatively, mix by hand until smooth.
Form into about 40 1-inch balls and arrange on waxed paper-lined baking tray. Chill 30 minutes. (Or freeze until solid, then pack into airtight containers to save for another meal. Do not thaw before cooking; add an extra 5-10 minutes cook time.)
Melt 2 tablespoons butter over medium-high in a large skillet and fry half the meatballs, turning frequently, until browned. They should not be cooked through at this point. Remove.
Add remaining butter and cook rest of meatballs the same way. Remove.
Add flour to skillet and whisk to cook until toasted.
Whisk in stock until smooth.
Add meatballs back to skillet and stir gently to coat in gravy. Simmer 10-15 minutes until thickened and meatballs are cooked through.