Boil the kettle and pour 150ml of boiling water into a mug, add the stock cube and stir until dissolved. Set aside and let cool for later. In a separate mug, crack and beat the egg and set aside. Pre heat the oven to 200c
Cube the bread (about 1cm cubes) and transfer to a mixing bowl. Drizzle over 1tbsp garlic oil. Rip up the rosemary or give it a rough chop, throw it in with the bread along with a crack of fresh black pepper and a pinch of salt. Mix thoroughly so the bread is coated in the oil.
On a baking tray covered with baking paper, bake the bread in the oven at 200c for around 15 minutes until golden and crisp.
Chop the celery and spring onion into thin strips. Heat 0,5 tbsp of garlic oil in a non stick pan. Add in the celery and fry on medium heat for 10 minutes. Add the spring onion and cook until wilted for around 5 minutes.
Place the cooked vegetables into a bowl and let cool for a couple of minutes.
When the bread is cooked, take it out of the oven and place in the bowl with the vegetables. Pour over the cooled stock and the egg.
Give a good mix until everything is coated evenly. Transfer to an oven proof dish and bake in the oven for ~20 minutes or until set and golden brown.
When the stuffing comes out of the oven, grate over the parmesan and sprinkle over the lemon zest.