Shepherd's Pie with Cheddar Cheese Mashed Potatoes - Rosalie Serving

Ingredients

• 1 tablespoon olive oil
• 1 to 2 tablespoons butter
• 1 small onion, diced
• ½ cup celery, diced
• 3 cloves minced garlic
• 2 pounds ground lamb
• Or lean ground beef
• 1 teaspoon kosher salt
• ½ teaspoon coarse black pepper
• 1/4 teaspoon paprika
• 1 teaspoon dried rosemary,
• Or 1 teaspoon herbs de Province seasoning
• 3 tablespoons flour
• 1 to 2 tablespoons Worcestershire sauce
• 2 tablespoons ketchup
• 2 ½ cups Kitchen Basics beef stock
• 4 pounds Yukon gold potatoes, quartered
• 2 teaspoons salt
• 1/2 cup butter
• ½ to 1 teaspoon kosher salt
• 1/4 teaspoon coarse black pepper
• Pinch of cayenne pepper
• 1/3 to 1/2 cup half and half
• 2 cups Irish white cheddar cheese, grated and divided
• 1 egg yolk
• 3 tablespoons half and half
• 1 (12-ounce) package frozen peas and carrots