Cottage Pie

Name: Cottage Pie
Prep time: 30 min
Cook time: 1 h
Total time: 1 h 30 min
Yield: 8
Ingredients: Ingredients; 2 lbs ground beef (80/20 blend); 2 medium onions, diced; 2 large carrots, diced; 1 cup frozen peas; 3 cloves garlic, minced; 2 tablespoons tomato paste; 2 tablespoons Worcestershire sauce; 1 cup beef broth; 2 tablespoons fresh thyme leaves (or 2 teaspoons dried); 2 bay leaves; 2 tablespoons all-purpose flour; 3 tablespoons olive oil; Salt and black pepper to taste; 3 lbs Yukon Gold potatoes, peeled and quartered; 1/2 cup whole milk; 4 tablespoons butter; 1/4 cup sour cream; 1 large egg yolk; 1 teaspoon salt; 1/2 teaspoon white pepper; 1/2 cup sharp cheddar cheese, grated (optional)