Lamb shepherd's pie with pumpkin

Instructions

1. Lightly spray a large, heavy-based saucepan or flameproof casserole pan with oil. Cook mince, over a high heat, for 8-10 minutes until browned and cooked through. Using a slotted spoon, transfer to a large bowl and set aside, covered.
2. Lightly spray the same pan with oil. Cook onions, carrots and celery over medium heat for 8-10 minutes, stirring occasionally, until soft. Add garlic and thyme and cook for 1 minute. Add flour and cook, stirring constantly, for 2 minutes. Return lamb to the pan and add tomato paste, stock and Worcestershire sauce. Bring to the boil, then reduce heat to low and simmer, covered, for about 30 minutes. Uncover and cook for a further 30-40 minutes, or until liquid has reduced and sauce has thickened.
3. Meanwhile, cook pumpkin in a large pot of boiling water for 20 minutes, or until pumpkin is tender. Add kale to the pot during the last 2 minutes of the pumpkin cook time. Drain and transfer pumpkin to a large bowl and kale to a small bowl. Mash the pumpkin until soft. Season with salt and pepper. Stir in kale and horseradish sauce.
4. Preheat oven to 180°C. Spoon lamb mixture into a medium baking dish (about 25cm x 17cm), then spoon over the mash, spreading evenly to cover the lamb. Bake pie for 25 minutes, or until the filling starts to bubble.