Shepherds Pie

Name: Shepherd's Pie
Ingredients: 1 1/2 lb. potatoes, peeled; Kosher salt; 4 tbsp. melted butter; 1/4 c. milk; 1/4 c. sour cream; Freshly ground black pepper; 1 tbsp. extra-virgin olive oil; 1 large onion, chopped; 2 carrots, peeled and chopped; 2 cloves garlic, minced; 1 tsp. fresh thyme; 1 1/2 lb. ground beef; 1 c. frozen peas; 1 c. frozen corn; 2 tbsp. all-purpose flour; 2/3 c. low-sodium chicken broth; freshly chopped parsley, for garnish