Shepherd's Pie - A better choice!

Ingredients

• 4 peeled white potatoes
• ½ cup milk
• 1/4 cup butter
• 500g beef mince
• 1 brown onion, diced
• 2 carrots, diced
• 2 celery stalks, diced
• 2 tbsp oil
• 3 cloves garlic, minced
• 1 tsp salt
• 1 tsp pepper
• 1 cup beef stock
• 1 ½ tbsp tomato paste
• 1 tbsp Worcestershire sauce
• 2 tsp rosemary, chopped
• 1 tbsp thyme, chopped
• 1 cup peas