Courgette with buttermilk + poppy seed dressing

In the summer our garden overflows with courgettes, and for weeks we have to come up with ingenious ways of using them. This is my (Alison’s) favourite – the dressing is gentle but a little tangy, and a spoonful of this goes well with grilled sardines or roast ham. Make this dish your own by adding soft herbs such as tarragon, or stirring in crushed garlic and a smidge of honey for sweetness. It’s best eaten on the day you make it.