Heat the oven to 180°C.
Cut the onions in half lengthways and roast them in the oven until just soft. Allow to cool, then push out the middle pieces to create 12 ‘petals’.
For the basil purée, blend 470g of basil leaves and 180ml of Knorr Greek Vinaigrette Salad Dressing in a blender on high speed until smooth. Season with salt and pepper.
In a bowl, combine the tomatoes, olives, cucumber, the remaining basil leaves and 15ml of Knorr Greek Vinaigrette Salad Dressing.
Brush four plates with the basil purée. Arrange the salad over the basil purée, sprinkle the crumbled feta on top, and balance the onion petals on top of the salad.
Carefully fill each onion petal with a teaspoon of Knorr Greek Vinaigrette Salad Dressing and serve immediately.