Preheat the broiler. In a large bowl, soak the bread in the milk for 1 minute, until softened. Squeeze out the excess milk and return the bread to the bowl. Add the eggs, onion, salt, paprika, dry mustard, pepper and mace and mix until smooth. Add the ground beef and mix until evenly combined.
Brush a large rimmed baking sheet with oil. Using a 2-tablespoon-size ice cream scoop, form the meat into 1 1/2-inch balls; roll until smooth. Transfer the meatballs to the baking sheet and brush the tops with oil. Broil 10 inches from the heat for about 10 minutes, shifting the sheet occasionally, until the meatballs are sizzling and browned.
Meanwhile, in a large, deep skillet, combine the ketchup, jelly, sherry and Worcestershire. Add 1/2 cup of water and bring to a simmer, whisking until the jelly is melted.
Using a slotted spoon, add the meatballs to the sauce and simmer over low heat until thickly glazed, about 15 minutes. Transfer the meatballs to a bowl and serve with picks.