Classic Meatloaf

Name: Classic Meatloaf
Ingredients: 2 medium onions, finely diced; 2 teaspoons sea salt; 1/2 teaspoon freshly ground black pepper; 3 tablespoons Worcestershire sauce; 2 teaspoons liquid smoke (optional); 1/4 cup bubbly water, seltzer, milk, or cream; 3/4 cup ketchup OR barbecue sauce; 1/2 cup fresh or dried parsley, minced (plus more for garnish, if you’d like); 6 eggs; 2 cups rolled oats OR bread crumbs (preferably sourdough); 3 pounds lean ground beef OR 2 pounds ground beef + 1 pound ground pork