Place the porcini in a small bowl, just cover with boiling water and leave to rehydrate.
Peel and finely chop the onion and garlic, then trim and finely chop the celery. Snap off and discard the woody asparagus ends, cut off the tips and roughly chop the stalks. Roughly chop the chestnut mushrooms.
Heat a splash of oil in a medium pan over a medium-low heat, add the onion, celery and a splash of water, then cook for around 5 minutes, or until softened but not coloured, stirring occasionally.
Scoop out, finely chop and add the porcini to the pan with the soaking water, leaving any gritty bits behind.
Bring 600ml of water to the boil in a medium pan, add the stock cube or pot and stir to dissolve. Keep over a low heat.
Place another pan over a medium heat with a drizzle of oil, then add the garlic, mushrooms and a small pinch of sea salt and black pepper. Cook gently for a few minutes, or until softened.
Pick and finely chop the parsley leaves, then add the stalks to the stock. Finely grate the cheese.
Once the vegetables are soft, stir in the rice and and fry for 1 minute until translucent. Pour in the wine (or replace with 50ml stock), and keep stirring until absorbed.
Turn the heat up to medium, then add a ladleful of hot stock (avoid the parsley stalks!). Keep stirring and adding stock, a ladle at a time, waiting for the rice to soak it all up before adding the next ladleful. Continue until you’ve added two-thirds of the stock.
Stir the asparagus and cooked mushrooms into the pan. Keep adding the remaining stock until the rice is just cooked and the risotto is nice and oozy – if you run out of stock, use boiling water.
Remove from the heat and stir in most of the cheese. Season to taste with salt, pepper and a squeeze of lemon juice, then cover and leave to sit for 2 minutes. Divide between your plates, then serve with the parsley and remaining cheese on top.