Mix all meatball ingredients, except the meat, in a large bowl. Add the ground meat and mix to combine using a fork or your hands.
Use your hands to shape into 1 inch balls (or slightly larger) and place on a rimmed baking sheet. Bake at 350 for approximately 30 minutes.
Wash and cut the potatoes into approximately 1 inch cubes. Place the potatoes into a large stockpot and cover with water. Boil for about 20 minutes, or until a fork can be easily inserted into the potatoes.
To make the gravy, melt the butter in a small saucepan. Add the flour and whisk to combine. Gradually add the beef broth and continue whisking and stirring until the gravy is thickened. Add cream of celery soup and additional water, if needed, to reach the desired thickness. If you opt not to use the soup, you may want to double the gravy recipe.
Serve meatballs and potatoes topped with gravy.