A lighter pesto

• 50–60 g/1¾–2¼ oz fresh basil leaves
• 1 tbsp roughly chopped parsley

Combine the basil, parsley, pine nuts, garlic, salt and pepper in a food processor or blender and whizz while you add the oil through the funnel until you have a paste. Spoon the pesto into a serving bowl, add the butter, cheeses and yogurt and place the bowl in a very low oven (120°F/250°C/gas mark ½).

Cook the pasta as usual and when al dente, drain, reserving a cupful of the water. T