Heat the oven to 180 c/ Gas 6. Deseed the squash and pumpkin and leave in large pieces. Rub the flesh with some oil and place onto a baking tray. Roast for approximately 30 mins or until softened and golden brown.
While the squash and pumpkin cooks, melt the butter with the remaining oil in a large saucepan. Add the onions, garlic and chilli. Cover and gently cook/sweat on a low heat for 15-20 mins until everything is completely soft.
Once the squash and pumpkin are cooked, take them out of the oven and leave to cool.
Once cooled, scoop the flesh from the roasted squash and pumpkin into the pan. Add the stock and crème fraiche.
Using a stick blender with care blend/ whizz until silky smooth.
Season and serve with finely chopped parsley sprinkled on top with a small spoon of crème fraiche.