Preparation time: 10 minutes
Cooking time: 15 minutes

500g/1lb tagliatelle
2 x 85g/3oz packs watercress, finely chopped (reserving a few leaves for garnish)
½ clove garlic, crushed
50g/2oz walnuts
100g/4oz freshly grated parmesan
2 tbsp mayonnaise
black olives and walnuts to garnish

Cook the tagliatelle into plenty of salted boiling water for approximately 15 minutes. Meanwhile, place the chopped watercress, garlic, walnuts, parmesan and mayonnaise in a food processor and process until smooth. Season to taste.

Rinse the pasta in boiling water, then stir in the pesto immediately. Serve the pasta topped with a sprinkling of olives and walnuts, and garnish with the remaining watercress leaves.