For the corned beef:

• 1 pound corned beef brisket, trimmed of fat
• ½ tsp mustard seeds
• 1 bay leaves, crushed
• 4–6 Allspice berries
• ¼ tsp salt
• ¼ tsp black pepper
• 4 cups water

For the soup:

• 2 tbsp butter
• 1 large onion, chopped
• 2 celery stalks, chopped
• 4 medium carrots, peeled and chopped
• 2 garlic cloves, minced
• 4 cups coarsely chopped cabbage
• ¼ cup pearled barley
• ½ pound Yukon gold potatoes, washed and sliced
• 1 bay leaf
• 2 tbsp fresh chopped parsley plus extra for garnish
• ½ tsp dried thyme
• 1 (14.5-ounce) can diced tomatoes
• 7 cups beef broth or stock
• salt, black pepper to taste