Preheat the oven to 200 °C (conventional oven)/ 180°C fan-forced (400° Fahrenheit/Gas 6). Line a baking tray with non-stick baking paper.
Place the pumpkin in the prepared baking dish. Drizzle over 2 tablespoons (40ml) of the olive oil, season with salt and toss to coat evenly. Cook for 25 minutes or until the pumpkin is tender and golden. Set aside to cool slightly before assembling the salad.
Place the sultanas in a small bowl and cover completely with water. Allow to soak for a minimum of 15 minutes.
Meanwhile, add the barley to a medium sized saucepan with 3 cups (750ml) of salted water. Bring to the boil, covered over high heat. Reduce heat to low, and simmer, covered for 20 minutes, or until the barley is al dente. Drain, reserving 2 tablespoons (40ml) of the cooking liquid. Refresh barley under cold water and transfer to a mixing bowl.
Chop 60g of the kale into very small pieces on a chopping board. Set aside. Drain the sultanas and set aside.
To make the kale pesto, roughly chop the remaining kale and process in a blender together with the remaining 100ml of olive oil and Parmigiano Reggiano (or Grana Padano). Alternatively, you could use a large mortar and pestle. Scrape down the sides occasionally and process until well combined. Add 1 tablespoon or more of the reserved barley cooking liquid, as required until you reach a smooth and creamy consistency. Season with sea salt to taste.
Add the kale pesto to the cooked barley and toss to evenly coat. Stir in the pumpkin, chopped kale, sultanas and mint until well combined. It is ready to serve – buon appetito.