Cavolo Nero and Walnut Pesto

Pesto is traditionally made with basil and pine nuts. But I make all sorts of versions using different nuts and greens, to increase the variety of what I eat and to make the most of seasonal produce throughout the year. Shop-bought pesto works fine, but homemade is quick to make and tastes better. Serve with pasta, spread on toast with a fried egg, drizzle over cooked vegetables or salads, or mash with a can of plain beans to make a great sandwich filling.