To prepare the stock mix the vegetable bouillon powder with 1 pint of boiling water and stir well. Set aside.
Break off the tough base of each asparagus stem and discard. Chop the rest into 1 cm pieces, leaving the tips whole.
Melt the butter in a medium sized saucepan then add the chopped onion and cook over a medium heat for about 5 minutes until softened and lightly coloured.
Stir in the asparagus making sure all the pieces are coated with the butter. Cook for 2 minutes, stirring often.
Add half the stock to the pan, season with a small pinch of salt and stir. Increase the heat and bring to a boil. Cover and simmer for 5 minutes.
Add the rice together with the remaining stock. Half cover and cook at a strong simmer for 15 minutes or until the rice is tender, stirring from time to time.
Remove the pan from the heat and stir in the parmesan. Season well with pepper and extra salt if needed. Serve immediately.