Method:
1 Bring the vegetable stock to the boil, add the lobster shells and parsley stalks and leaves, season with salt and pepper and reduce to a simmer, simmer for 8-10 minutes, strain stock into a jug.
2 Heat oil in a frying pan over medium heat, cook garlic and onion for 2-3 minutes, add mushrooms, asparagus, rice and vinegar and cook for a further minute.
3 Add simmering stock, 1 ladleful at a time. Stir with a wooden spoon until all liquid has been absorbed. Season with salt and pepper.
4 Spoon risotto into a bowl and scatter with parmesan shavings with a drizzle of olive oil to serve.