Place a medium size pot on high heat filled with the vegetable stock. Add the quinoa, bring to a boil, cover with the pot’s lid, reduce the heat and simmer for 10’. Add the sweetcorn and peas and cook for 2’ more. Don’t overcook either the quinoa nor the sweetcorn and peas, you want them a bit crunchy. Take out of the pot and run through fine sieve to drain, add to a bowl and pour half the lemon juice. Toss and keep aside to cool.