Meatloaf Casserole

Name: Meatloaf Casserole
Ingredients: 1 1/2 pounds russet potatoes; 1/2 cup half-and-half; 5 tablespoons unsalted butter; 1 1/2 teaspoons kosher salt, divided; 3 cloves garlic, minced and divided; 1/4 cup freshly chopped chives; 2 egg yolks; 2 tablespoons vegetable oil; 1 medium sized onion, diced; 3/4 cup diced green pepper; 1/2 cup diced celery; 2 pounds lean ground beef; 1 cup tomato sauce; 2/3 cup breadcrumbs; 1 1/2 tablespoons Worcestershire sauce; 1 1/2 tablespoons tomato paste; fresh parsley for garnish (optional)