Bring a pot of water to the boil and cook the sugar snap peas and beans for about 3 minutes. Add the frozen peas and cook for a further minute or two. If you are using fresh peas, they will take a minute or two longer too cook, so add them about 2 minutes after the beans.

Drain and run the vegetables under cold water until they are completely cooled (you can add a few ice cubes to help cool them down quickly)

Toss with the vinaigrette and red onion, check the seasoing and if necessary add salt and pepper, and serve with Parmesan shaved over the top.