Bring a large pan of salted water to the boil and add the peas, courgettes and asparagus (NB - these can be substituted for similar weights of other green spring vegetables such as broad beans, and it is OK to use frozen peas if that is all that’s available). Boil for 3 minutes.
Remove from heat and drain, reserving some of the water.
Place half the vegetables, the herbs and the olive oil into a food blender. Add a little of the reserved cooking water (maybe 50ml). Blend to a puree and set aside. Cool the remaining cooked vegetables under some cold water and set them aside.
Heat the butter in a large pan over a medium heat. Add the shallots and garlic and cook for 2 minutes. Then add the rice and cook for a further 2 minutes. Add the wine and bring to the boil. When it boils, start a 15 minute timer. Simmer for a couple of minutes, stirring well.
Keeping the timer running, open the pouch of stock. Add a little at a time to the pan, keeping it boiling gentle and stirring the whole time. Keep on adding until it is all used up. After 15 minutes all the stock should be added and much of the liquid will have been absorbed. Add the puree and the vegetables to the pan and return to a simmer. Cook for 3 more minutes, after which the rice should be nicely cooked (should have a little bite to it).
Stir in the Parmesan cheese and leave to rest for a couple of minutes. Serve in bowls, garnishing with some herbs or watercress leaves.