Start water boiling for potatoes. (Salt, if desired). Preheat oven to 375degF.
In a mixing bowl, combine meatball ingredients. Using a 1½inch food scoop to portion out the mixture into balls. Roll between your palms to shape.
Add potatoes to boiling water. Cook until fork tender (about 20 minutes).
In a large sauce pan over medium high heat, add formed meatballs. Cook on each side about 30 seconds (just searing the outside). Then transfer to a cooking rack over a parchment paper covered baking sheet. Once all have been seared place in the oven and bake for 30 minutes.
In same pan used to sear the meatballs, add butter. Once melted add beef broth, worcestershire and seasonings. Bring just to a bubble and remove about ½ cup of the liquid to a glass measuring cup. Add cornstarch and whisk vigorously. Return mixture to pan and whisk together. Reduce heat to medium low and let simmer and thicken.
Drain potatoes and add to large mixing bowl. Add melted butter, salt, pepper and heavy cream. Smash and combine until desired level of smoothness.
In a bowl, add a portion of potatoes, and 5-7 meatballs. Ladle pan gravy over top. Sprinkle with parsley, if desired.