Preheat oven to 175°C. Heat olive oil in a large oven-safe pot over medium heat. Add onion and garlic and cook until softened, about 5 minutes.

Place lamb shanks into the pot and pour in wine and beef stock. Bring to a boil then season with oregano, bay leaves, salt and pepper.

Cover the pot with lid and transfer to preheated oven. Bake for 2 hours or until lamb shanks are cooked through and tender.

Meanwhile, bring a large pot of salted water to a boil. Add potatoes and garlic, lower heat to medium, and simmer until potatoes are tender (15 to 20 minutes).

Heat butter in a small saucepan over medium heat. Add milk to the pan and stir until combined. Pour cream sauce into cooked potatoes and mash until combined. Season with salt and pepper.

Bring a pot of salted water to a boil and cook peas according to package instructions.

To serve, divide mashed potatoes into individual bowls and top with lamb shanks, peas and gravy from the pot. Enjoy!