Preheat the oven to 120°C/½ gas mark. Peel the apples, then cut in half right through the stem and remove the core. Using a sharp knife, carve a face on the rounded side of the apple and use a melon baller for carving out the eyes. Put the lemon juice in a bowl with the apples, then top up with water to cover. Set aside for 10 minutes to prevent the apple from browning too much in the oven.
Put the apples on a lined baking tray, face side up, and bake in the oven for 1½ hours. They should begin to dry around the edges. Remove from the oven and set aside.
Meanwhile, put the remaining ingredients into a large saucepan. Bring to the boil then heat gently for 15 minutes, until the flavour infuses. Remove the cinnamon sticks, then serve in a punch bowl or cauldron with the apples floating on top.