Bake in a moderate oven (160° C, 320° F, Gas Mark 3) for around 30 minutes, or until golden brown and a little crispy on top.
Remove from the oven and leave to stand for at least 15 minutes before turning out. (Put a large plate over the top of it before turning over and out - you can also tap the base of the inverted baking dish and loosen the edges with a knife to assist unmoulding.
Serve cut into wedges (like a cake) accompanied by the remaining sauce and meatballs.