Mikey's Meatloaf

Ingredients

• 3 tablespoons unsalted butter
• 1 medium yellow onion, finely chopped
• 1 stalk celery, finely chopped
• 3 cloves garlic, finely chopped
• 1 teaspoon dried thyme
• 1 tablespoon Dijon mustard
• 1 tablespoon reduced-sodium soy sauce
• 1 tablespoon tomato paste
• 1 tablespoon Worcestershire sauce
• 2 large eggs
• 1/2 cup whole milk
• 1/2 teaspoon unflavored powdered gelatin
• 1 1/2 pounds lean ground beef
• 1/2 pound ground pork
• 1/2 cup saltines, ground into fine crumbs
• kosher salt, to taste
• freshly ground black pepper, to taste
• 1 cup ketchup
• 2 tablespoons brown sugar
• fresh parsley leaves, optional, to taste, for garnish