Beef shepherd’s pie

Ingredients

• 1 1/2 pounds russet or Yukon gold potatoes, peeled and cut in quarters
• 1/4 cup sour cream
• 1/2 cup milk
• 6 tbsp butter
• 2 tsp sea salt or kosher salt
• 1 pinch freshly ground white pepper
• 2 tbsp extra virgin olive oil
• 3 tbsp butter
• 1/2 cup onion diced
• 3 carrots (small to medium-sized), peel and slice
• 2 ribs celery, chopped
• 2 cloves garlic, minced
• 1 pound lean ground beef
• 1/2 tsp dried oregano
• 1 pinch freshly ground pepper
• 3 tbsp tomato paste
• 2 tsp Worcestershire sauce
• 1/4 cup beef broth
• 1/4 to 1/2 cup frozen peas