Cut the squash in half, remove the seeds and cut in quarters. Place on enamelled GN container, drizzle with olive oil, season with salt and pepper and sprinkle with rosemary sprig. Place into a preheated Retigo combi oven using hot air, 180°C and roast for 15-20 minutes. Chopp and fry some peeled onion, put some vegetable stock, bring it to the boil and add the roasted squash. Use the stick blender to blitz it to a fine cosistency. Garnish with quenelle of sauer cream and a touch of olive oil.