The height of summer is the time to enjoy these twice-cooked vegetables. Salsa all’agresto is an Italian sauce which dates back to the Middle Ages. Similar in make-up to pesto, made with nuts, oil and herbs, but with the addition of verjuice (or unripened grape juice), it provides an intriguing flavour that gives us a glimpse of what people ate hundreds of years ago. If you can’t find verjuice, try a mix of white wine vinegar, lemon juice and a little sugar. Serve with crusty bread to mop u