Simmer the stock for 10 minutes with the asparagus trimmings and pea pods; these will intensify the flavour. Strain into a jug.
While the stock is simmering, heat 1 tbsp of the oil in a wide, shallow pan. Tip in the onion and fry gently for 5-6 minutes, stirring, until it is soft but not coloured. Add the rice and continue to stir and cook for 1-2 minutes until the grains become see-through at the edges and begin to make ‘clicking’ noises.
Add the wine (it should bubble and evaporate), then 50ml/2fl oz of the stock. Stir well and simmer gently until all the liquid has been absorbed. Now pour in another 50ml/2fl oz stock and stir again. Continue adding the stock and stirring. After about 7 minutes, when half the stock has been added, swirl in the asparagus and peas. Carry on adding stock in small amounts until it has been absorbed; this will take about 10 more minutes. Now the risotto should be a little wet and sloppy and the rice tender with a nutty bite.
Turn off the heat, then gently stir in the grated Parmesan, taste and season. You may need only a little black pepper as the Parmesan and stock are both salty. Spoon the risotto on to a plate, top with the rocket, drizzle with the remaining olive oil and scatter with Parmesan shavings. Pour yourself a glass of wine and enjoy your meal.