Wash and dice the courgettes. Cook them for 5 mins in salted boiling water adding a few drops of lemon juice. Drain them and set the cooking water aside for later use.
Prepare the couscous following the instructions on the packet, using the “recycled” water you used to cook the courgettes. Thinly slice the radishes and dice the apple. Finely chop the mint leaves. Mix the couscous with the courgettes, radishes and apple. Add the mint and season with the vinaigrette, obtained by mixing lemon juice, oil, salt and pepper (use one spoon of lemon juice for every 2 spoons of oil). Blend and serve. You can complete the couscous with flaked toasted almonds.

Green idea: as well as reusing the water used to cook the courgettes, you can make the dish even “greener” by turning the radish remains (the leaves) into a novelty “pesto”.
Mix the radish leaves in a blender, wash and drain a few walnuts and almonds and add some extra virgin olive oil, a pinch of salt and black pepper. Then use the pesto as a pasta sauce or to add to vegetable creams, adding a spicy “green” touch.