Finely chop the onion, garlic, carrot and rosemary leaves.
Heat the oil in pan and gently fry the onion until softened, then add the garlic, carrot and rosemary. Put a lid on and sauté for 8 minutes over low heat.
Add the tomatoes, gravy and/or stock. Bring to the boil and cook over low heat for 10 minutes, then add the chickpeas and your chosen greens. Cook for another 5 minutes.
Add more stock if the stew is too thick.
Cut the lamb pieces into smaller pieces, if needed and stir into the stew.
Transfer the stew into a deep baking dish and rest until you’re ready to make the pie.
Heat the oven to 200°C.
Unroll the pastry, then cut it about 2 cm bigger than the dish. Put this cut-out piece on top of the dish, pressing the pastry around the edges to seal.
Use any remaining pastry to create decorations - flowers, eggs, bunnies or other motives. Press these onto to pastry with the beaten egg, if used.
Make a couple of incisions in the pastry to allow the steam to escape, then brush the pastry with the egg for a golden, crispy finish.
Bake for 20 minutes or until the pastry is golden and it has risen nicely.
Serve warm.