For the meatballs: 3/4 pound ground chuck 3/4 cup fine dry bread crumbs 3/4 teaspoon salt 1/2 teaspoon black pepper 2 tablespoons minced onion 1-1/2 teaspoons drained bottled horseradish 2 large eggs, beaten lightly 2 tablespoons unsalted butter Make the sauce: In a bowl whisk together the ketchup, the water, the vinegar, the brown sugar, the onion, the Worcestershire sauce, the mustard, the Tabasco, the cayenne, and salt and black pepper to taste. Make the meatballs: In a bowl combine gently the chuck, the bread crumbs, the salt, the pepper, the onion, the horseradish, and the eggs and form level tablespoons of the mixture into meatballs. In a large heavy skillet heat 1 tablespoon of the butter over moderately high heat until the foam subsides and in it brown well half the meatballs, shaking the skillet to maintain the round shapes. Transfer the meatballs with a slotted spoon as they are browned to paper towels to drain and brown the remaining meatballs in the same manner. Add the sauce to the skillet and simmer it, stirring, for 1 minute. Return the meatballs to the skillet and simmer the mixture for 3 to 5 minutes, or until the meatballs are heated through. Makes about 36 meatballs.