Preheat your oven to 180°C (160°C fan) or gas mark 4.
In a large pan, heat the olive oil over medium-high heat. Add the lamb mince and cook until browned, breaking it up as you go. Use a slotted spoon to remove it to a bowl and set aside. A deep, non-stick pan like this one is ideal for browning the mince and simmering everything together. Reduce the heat to medium-low. In the same pan, add the leeks, onions, and carrots. Cook gently for around 15 minutes, stirring regularly, until softened and lightly golden.
Return the browned lamb to the pan. Stir in the bay leaf, flour, and rosemary. Add the tomato purée and prepared stock, mix well, then let it simmer for 10 minutes.
Stir in the peas and a good grind of black pepper. Divide the mixture evenly between 4 individual ovenproof dishes (or use one large baking dish).
Layer the sliced potatoes and swede over the top of each dish, overlapping slightly. Season with more black pepper.
Bake in the oven for 55 minutes, or until the potatoes and swede are tender. Brush the tops lightly with olive oil and return to the oven for another 5 minutes until golden and crisp on top. Oven gloves like these are a must when juggling hot dishes, especially if you’re serving straight from the oven. Serve hot, with steamed greens on the side if you like. I love baking these in individual dishes like these, they look great and make for easy serving.