Butternuts are one of the hardest vegetables to cut. Always use a large sharp knife. The easiest way is to top and tail the butternut, then cut it across into two. Stand each half on one end and cut away the skin from top to bottom. Halve each piece lengthways and remove the seeds. Heat the oil and butter in a large saucepan, add the onions and garlic and gently sauté.
While the onions