Blake's Shepherd's Pie

Ingredients

• 1 lb (450g) ground lamb (or beef, if preferred)
• 1 medium onion, diced
• 2 carrots, diced
• 2 garlic cloves, minced
• 1 cup (150g) frozen peas
• 2 tablespoons (30ml) tomato paste
• 1 teaspoon (5g) Worcestershire sauce
• 1 teaspoon (5g) dried thyme
• 1 teaspoon (5g) dried rosemary
• Salt and pepper to taste
• 1 cup (240ml) beef or vegetable stock
• 2 lbs (900g) russet potatoes, peeled and quartered
• 4 tablespoons (56g) unsalted butter
• ½ cup (120ml) whole milk
• Salt to taste